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SWBSS 2017

Fourth International Conference on Salt Weathering of Buildings and Stone Sculptures

20 – 22 September 2017 – Fachhochschule Potsdam

Fourth International Conference on

Salt Weathering of Buildings and

Stone Sculptures

Programme and abstracts

University of Applied Sciences Potsdam, Germany

20-22 September 2017

Layout: Semler Grafik oHG, BerlinCover image: Photo: Hans-Jürgen Schwarz, Design: Benita Lohse

Welcome to Potsdam

Welcome at the University of Applied Sciences in Potsdam!

The first SWBSS event was held in Copenha-gen, Denmark in 2008, with Lisbeth Ottosen as driving force, the second was arranged by Ioannis Ioannou and Magdalini Theodoridou in Limassol, Cyprus, in 2011, and the third SWBSS conference was organized by Hilde De Clercq and colleagues at the Royal Institute for Cultural Heritage in Brussels, Belgium.

This is the fourth conference in the series. It is a great pleasure to see that SWBSS 2017 has been met with interest from so many dif-ferent countries both in Europe and outside of Europe.

We received around 50 contributions, con-sisting of papers and abstracts and bringing together conservators, restorers, engineers, scientists, young students and experienced researchers.

The success confirms the significance of the SWBSS agenda for the scientific community. Being aware that salt crystallization is of ma-jor importance in the weathering of porous building materials, I do hope that this confe-rence contribute to an exchange of knowled-ge, create new solutions for the preservation of our cultural heritage and stimulate new research ideas and future collaborations wi-thin this interesting field.

On behalf of the Conference Organizing Committee and the participants I would like to take the opportunity to thank the many reviewers of the Scientific Committee who so generously gave their time to ensure that the papers accepted are of a high quality and re-present a true advance in the state-of-the-art.

Furthermore, I would like to thank Hilde De Clercq, Royal Institute for Cultural He-ritage, Brussels, and my colleagues of Salze im Kulturgut e. V., especially Mike Steiger and Hans-Jürgen Schwarz, for co-organizing this SWBSS conference. Thanks also to the Prussian Palaces and Gardens Foundation Berlin-Brandenburg, particularly to Kathrin Lange and Roland Will, for organizing the

excursion. And without the help of my col-leagues and the students of our University we could not have organized this internatio-nal conference: thank you all!

Last but not least, I would like to express my deepest gratitude to our sponsor The Deutsche Bundesstiftung Umwelt DBU (Ger-man Federal Environmental Foundation) for supporting the printing of the conference proceedings.

I sincerely hope that you will enjoy SWBSS 2017 and wish you a pleasant stay in Pots-dam!

Steffen Laue

Conference ChairUniversity of Applied Sciences PotsdamDepartment for Conservation and Restoration

Conference Details

SWBSS 2017Scientific Committee

De Clercq, Hilde – Royal Institute for Cultural Heritage, Brussels, BelgiumDiaz Gonçalves, Teresa – Laboratório National de Engenharia Civil, Lisboa, PortugalEspinosa-Marzal, Rosa M. – University of Illinois at Urbana-Champaign, USAFlatt, Robert – ETH Zürich, SwitzerlandHamilton, Andrea – University of Strathclyde, Glasgow, UK Ioannou, Ioannis – University of Cyprus, Nicosia, CyprusLaue, Steffen – University of Applied Science Potsdam, GermanyLubelli, Barbara – Delft University of Technology, The NetherlandsOttosen, Lisbeth – Technical University of Denmark, Lyngby, DenmarkSiedel, Heiner – Dresden University of Technology, GermanySteiger, Michael – University of Hamburg, GermanyTörök, Ákos – Budapest University of Technology and Economics, HungaryVergès-Belmin, Véronique – Laboratoires de Recherche des Monuments Historiques,

Champs-sur-Marne, France

Organizing committee

Laue, Steffen – University of Applied Science Potsdam and Salze im Kulturgut e. V. Steiger, Michael – University of Hamburg and Salze im Kulturgut e. V.De Clercq, Hilde – Royal Institute for Cultural Heritage, Brussels, Belgium

Sponsored by

The Deutsche Bundesstiftung Umwelt DBU (German Federal Environmental Foundation)

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Conference Venue

The conference takes place in the Main Buil-ding (HG) of University of Applied Sciences in Potsdam (UoASP). Address: Kiepenheuerallee 5, D-14469 Potsdam.

How to get to the UoASP by public transportation

From the main station take either tram 92 to „Kirschallee“ or tram 96 to „Viereckremise“, and get off at „Campus Fachhochschule“ – duration approx. 12-15 min.

Registration

The registration desk is located in the entrance foyer of the Main Building. It opens on Wed-nesday 20th September at 08:00 am and will be open all days during the conference. If you have any questions, please, ask at the regist-ration desk.

Oral presentations

Oral presentations are 15 minutes in length, followed question time for 3 minutes and then 2 minutes to facilitate changeover to the next speaker.

Coffee breaks and Lunches

Refreshments during the coffee breaks are available free of charge for registered partici-pants an the conference venue. Lunch will be offered by the Mensa of the UoAS (self-pay)

Campus of University of Applied Sciences in Potsdam Internet

WIFI access is provided.Login WLAN: FHP GuestUsername: swbsspassword: swbss2017

Excursion

The excursion starts on Thursday 21 Septem-ber, 01:45 pm at the UoASP and we will visit the Park Sanssouci in Potsdam. More infor-mations will be provided during the confe-rence.

Social events

Wednesday, 20 September 201705:30 pm – Guided tours to the workshops of the Department of Conservation and Resto-ration 07:00 pm – Evening Reception in the hall of the Main Buildung of UoASP

Thursday, 21 September 201707.30 pm – Conference Dinner at the Meierei in Potsdam (see page 42)

Friday, 22 September 201706:45 pm – Fair well drink in the Main Buil-ding of UoASP

Proceedings of the conference

A hard cover version of the proceedings can be purchased at the registration desk for 30,-€. A digital version can be downloaded on www.saltwiki.net

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SWBSS 2017 – Program

Tuesday, 19 September 2017

19:00Come together at Café Heider (self-pay)Address: Friedrich-Ebert-Str. 29, D-14467 Potsdam (in the city center of Potsdam, close to many hotels)

Wednesday, 20 September 2017

08:00 Registration

09:00 Welcome

Steffen Laue – UoAS PotsdamEckehard Binas – President of the UoAS PotsdamPaul Bellendorf – The Deutsche Bundesstiftung Umwelt DBU

(German Federal Environmental Foundation)

Salt sources, transport and crystallization Session chair: Robert Flatt

09:30Traffic-induced salt deposition on facades M. Auras (Mainz, Germany)

09:50Wick action in cultural heritageL. Pel & R. Pishkari (Eindhoven, The Netherlands)

10:10A preliminary study on dynamic measurement of salt crystallization and deliquescence on a porous material surface using optical microscopeM. Abuku, D. Ogura & S. Hokoi (Higashi-Osaka, Japan)

10:30 Coffee break

Measurement techniques and experimental studies Session chair: Andrea Hamilton

11:00New approaches to assess salt induced decay in building stonesJ. Dassow, A. Leslie, S. Hild, P. Harkness, L. Naylor & M. Lee (Glasgow, UK)

11:20Diagnostics and monitoring of moisture and salt in porous materials by evanescent field dielectrometryC. Riminesi & R. Olmi (Florence, Italy)

SWBSS 2017 – Program11:40

Determination of the water uptake and drying behavior of masonry using a non-destructive methodA. Stahlbuhk, M. Niermann & M. Steiger (Hamburg, Germany)

12:00Measurement of salt solution uptake in fired clay brick and identification of solution diffusivityE. Mizutani, D. Ogura, T. Ishizaki, M. Abuku & J. Sasaki (Kyoto, Japan)

12:20 Lunch

Session chair: Lisbeth Ottosen

13:30How surfactants affect salt crystallization in sandstones?M. Qazi, D. Bonn & N. Shahidzadeh (Amsterdam, The Netherlands)

13:50Local strain measurements during water imbibition in tuffeau polluted by gypsum M.A. Hassine, K. Beck, X. Brunetaud & M. Al-Mukhtar (Orleans, France)

14:10Assessment of the durability of lime renders with Phase Change Material (PCM) additives against salt crystallization L. Kyriakou, M. Theodoridou & I. Ioannou (Nicosia, Cyprus)

14:30 Poster session (2 min oral presentations of each poster) – see page 36

15:00 Coffee break and poster session

Measurement techniques and experimental studies Session chair: Ioannis Ioannou

16:00Biogenic hydroxyapatite – a new material for conservationA. Hamilton, R. Turner & J. Renshaw (Glasgow, UK)

16:20Electrode placement during electro-desalination of NaCl contaminated sandstone – simulating treatment of carved stonesL. M. Ottosen & L. Andersson (Lyngby, Denmark)

16:40 Salt crystallization effect on the protective treated sandstone by SiO2-based and POSS-based hybrids during hygrothermal cycles M J. Jia, L. He, J Y. Liang and X. Zhao (Xi’an, China)

17:15Guided tours to the conservation and restoration workshops (UoAS Potsdam)

19:00Reception at the University of Applied Sciences Potsdam (in the building of the conference)

SWBSS 2017 – Program

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Thursday, 21 September 2017

Studies for conservation issues Session chair: Barbara Lubelli

09:00Efficiency of laboratory produced water repellent treatments on limestone C. Charalambous & I. Ioannou (Nicosia, Cyprus)

09:20

Environmental control for mitigating salt deterioration by sodium sulfate on Motomachi Stone Buddha in Oita prefecture, JapanK. Kiriyama, S. Wakiya, N. Takatori, D. Ogura, M. Abuku & Y. Kohdzuma (Kyoto, Japan)

09:40Management of sodium sulfate damage to polychrome stone and buildingsD. Thickett & B. Stanley (English Heritage, UK)

10:00Conservation of marble artifacts by phosphate treatments: Influence of gypsum contaminationE. Sassoni, G. Graziani, E. Franzoni & G.W. Scherer (Bologna, Italy)

10:20 Coffee break

Salt crystallization tests Session chair: Mike Steiger

10:50Salt crystallization tests: Focus on their objectiveE. Charola, I. Rörig-Dalgaard, J. Chwast, J. Elsen & H. Janssen (Washington, DC, US)

11:10Mitigating salt damage in lime-based mortars with mixed-in crystallization modifiers S. Granneman, B. Lubelli & R.P.J. van Hees (Delft, The Netherlands)

11:30Artificial decay of rocks for stone treatments evaluation in laboratory D. Costa (Lisbon, Portugal)

11:50First results of the RILEM TC 271 ASC – A review of salt crystallization testsB. Lubelli & RILEM TC-ASC working group (Delft, The Netherlands)

12:10Predicting salt damage in practice: A theoretical insight into laboratory testsR. Flatt & RILEM TC-ASC working group (Zürich, Switzerland)

12:30 Lunch

13:45 Excursion to the Park Sanssouci

19:30 Conference dinner in the Meierei – Park New Garden

SWBSS 2017 – Program

Friday, 22 September 2017

Studies for conservation issues Session chair: Heiner Siedel

09:00

Combined non-destructive measurements to understand the salt weathering at the Torre de Quintela, PortugalA. M. Ricardo, W. Wedekind, L.M.O. Sousa & S. Siegesmund (Göttingen, Germany)

09:20Protecting Pompeii with clay barriersM. Michette & R. Kilian (Oxford, UK)

09:40How not to bother soluble salts while groutingC. Pasian, F. Piqué, C. Riminesi & A. Jornet (Lugano, Switzerland)

10:00Early treatments for porous plaster and salt-damaged wall decorations in ScandinaviaM.C. Christensen, H. Andersson, I. Brajer & P. Klenz Larsen (Lyngby, Denmark)

10:20 Coffee break

Conservation issues and salt reduction Session chair: N.N.

10:50The application of hydroxyapatite-based treatments to salt-bearing porous limestones: A study on sodium sulphate-contaminated Lecce StoneG. Graziani, E. Sassoni, G.W. Scherer & E. Franzoni & (Bologna, Italy)

11:10Moisture transport during poultice applicationC. Franzen, M. Aulitzky & S. Pfefferkorn (Dresden, Germany)

11:30Evaluation of desalination and restoration methods applied in Petra (Jordan)W. Wedekind & H. Fischer (Göttingen/Berlin, Germany)

11:50Desalination of Cotta type Elbe sandstone with adapted poultices: Optimization of poultice mixtures and application termsJ. Maitschke & H. Siedel (Potsdam/Dresden, Germany)

12:10 Lunch

Salt reduction and case studies Session chair: Ákos Török

13:20Salt extraction by poulticing – results of a pre-investigation at the archeological site of Coudenberg S. Godts, H. De Clercq & M. Rich (Brussels, Belgium)

13:40

Tracing back the origins of sodium sulfate formation on limestone as a consequence of a cleaning campaign: the case study on Charité and Espérance sculptures of Chartres cathedralS. Benkhalifa, V. Vergès-Belmin, O. Rolland & Leroux Lise (Paris, France)

SWBSS 2017 – Program

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14:00Granite and schist masonry desalination by poultices at Jacobine Church in Morlaix, FranceB. Brunet-Imbault, B. Reidiboym & C. Guinamard (Studiolo, Paris, France)

14:20Investigation of salts sources at the Karadjordje‘s Gate on the Belgrade fortressM. Franković, N. Novaković, S. Erić, P. Vulić & V. Matović (Belgrade, Serbia)

14:40 Coffee break

Case studies Session chair: Véronique Vergès-Belmin

15:10

Salt content of dust and its impact on the wall paintings of the church St. Georg at the UNESCO World Heritage site Monastic Island of Reichenau in GermanyJ. Frick, M. Reichert, & H. Garrecht (Stuttgart, Germany)

15:30Investigation and examination of a degraded Egyptian painted limestone relief from Tell Hebua (Sinai)E. Mertah, M. Othman, M. Abdelrahman, M. Fatoh, S. Connor (Cairo, Egypt)

15:50Salt-induced flaking of wall paintings at the Mogao Grottoes, China L. Wong, S. Bomin, W. Xiaowei, A. Rava & N. Agnew(The Getty Conservation Institute, L.A., US)

16:10Investigation and conservation concept of salt damaged epitaphs in the church of Werben (Saxony-Anhalt)S. Laue, D. Poerschke & B. Hübner (Potsdam, Germany)

16:40 Closing remarks & Fair well drink

SWBSS 2017 – Program SWBSS 2017 – Abstracts

Wednesday, 20 September 2017

Salt sources, transport and crystallization

Traffic-induced salt deposition on facades

Michael Auras*Institut für Steinkonservierung e. V., Mainz, Germany* auras@ifs-mainz.de

AbstractAir pollution has been reduced significantly

in Germany during the last decades. Never-theless high pollution levels are recorded in urban environment along heavy-trafficked roads. Relevant portions of the emissions of nitrogen oxides and fine particulate matter are caused by car traffic. The change of en-vironmental conditions has led to a change of salt deposition on facades. Actual research results show high concentrations of nitrogen oxides at historical facades but contradictory data for the deposition of nitrates. Additio-nally, the redispersion of de-icing salt by car traffic leads to a deposition of chlorides on fa-cades not only in the base zone.

Keywords: Air pollution, traffic emissions, salt input

Wick action in cultural heritage

Leo Pel* and Raheleh PishkariEindhoven University of Technology, The Netherlands* l.pel@tue.nl

Abstract Salts crystallization is one of the main de-

gradation mechanisms of historical objects, e.g., masonry. In this study we looked at a special case often encountered in marine en-vironment, i.e., wick action. This is a steady state situation in which one end of an object is continuously absorbing a salt solution, e.g., sea water, whereas at the same time at other side there is continuous drying. As a result there will be a continuous flux of ions to-wards the drying surface and the concentra-tion at the drying surface will slowly increa-se, resulting eventually in crystallization.

In this study we looked at wick action for a 1m NaCl solution using a biomicritic limes-tone from Sardinia, which is found in many cultural heritage objects. To measure both moisture and salt content simultaneously, we have used a specially designed Nuclear Magnetic Resonance (NMR) set-up. The wick action experiment was performed for over 40 days. The results show that the concentration over 40 days slowly increases at the top until the saturation concentration is reached. It is shown that the concentration profiles can be modelled by a simple analytic solution of the advection-diffusion equation describing the ion transport.

Keywords: Wick action, drying, salt crystalliz-ation, Nuclear Magnetic Resonance

A preliminary study on dynamic measure- ment of salt crystallization and delique-scence on a porous material surface using optical microscope

M. Abuku1,*, D. Ogura2 and S. Hokoi2

1 Faculty of Architecture, Kindai University2 Graduate School of Engineering, Kyoto University* abuku@arch.kindai.ac.jp

AbstractThis paper reports on our preliminary

attempt to perform dynamic laboratory mea-surements of salt crystallization and subse-quent deliquescence on a surface of a porous material specimen (autoclaved aerated con-crete as a model material) by using a high- resolution digital optical microscope that allows generating three-dimensional images. A specimen that is initially filled with a NaCl solution is dried in a room at ~ 26°C and ~ 40%RH for 14 days and is then wetted in a desiccator at ~ 95%RH during the next 14 days. A temporal change of the spatial distri-bution of the volume occupied by salt crys-tals on the specimen surface is determined based on the contrast between two microsco-pic images successively taken with a certain

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Measurement techniques and experimental studies

SWBSS 2017 – Abstracts

interval of time. The mass of the specimen is also measured simultaneously to determine the rate of water evaporation/absorption. The results show that salt crystallization during drying is not spatially uniform throughout the specimen surface, which likely depends on the spatial distribution of the pore struc-ture in the specimen, and salt crystal deli-

quesces faster near the edges of the specimen than in the centre, which indicates a stron-ger dependency of salt deliquescence on the geometry of the specimen than on the inner pore structure of the specimen.

Keywords: light microscopy, efflorescence, sodium chloride, absorption/desorption

New approaches to assess salt induced decay in building stones

J. Dassow1, A. Leslie2, S. Hild3, P. Harkness4, L. Naylor1, M. Lee1

1 University of Glasgow (School of Geographical and Earth Sciences)

2 Historic Environment Scotland3 University of Glasgow (School of Physics and Astro-

nomy)4 University of Glasgow (School of Engineering)

AbstractNew approaches to assess stone decay are

required to gain a better understanding of the time scale and magnitude of weathering processes. Deciding on the best conservation strategy for historic buildings suffering from salt decay can be challenging, if the state of decay is only investigated on the surface. Our project aims to develop two new minimally or non-invasive techniques that can assess the state of decay of building stones in situ below the surface. The techniques focus on assessing sandstone masonry with an ultra-sonic drilling tool to estimate the structural properties, and a laser interferometer to mea-sure dilation over time.

The laser interferometer can measure con-traction or expansion of a sample on the na-nometre scale. Salt crystallisation in porous systems can be analysed with very high pre-cision under any temperature and humidity condition that enable salt growth. Characte-rising dilation events through precise measu-rement of displacement and event frequency can provide insight on the intensity of decay of the building material.

The ultrasonic drilling tool monitors the power that is needed to drill into a sample

up to a depth of 4 cm. This technique drills a hole of 3 mm diameter with less force exer-ted on the sample than conventional drilling techniques; it enables penetration of rocks with compressive strength in excess of 90 MPa. The variation of the power feedback sig-nal during drilling allows the sample’s struc-tural properties, like porosity, to be deduced. Salt accumulation in the pores can then be located.

These developed techniques provide a more precise identification of salt weathering in building stones, and can be scaled up from the lab to the field. Potentially the devices can be used in situ under site conditions to enable a precise characterisation of the state of decay.

Keywords: building stone decay, ultrasonic drilling, laser interferometry, sandstone weathering

Diagnostics and monitoring of moisture and salt in porous materials by evanescent field dielectrometry

C. Riminesi1,* and R. Olmi2

1 Institute for the Conservation and Valorization of Cultural Heritage (ICVBC), National Research Council, Firenze (IT)

2 Institute of Applied Physics (IFAC), National Research Council, Firenze (IT)

* cristiano.riminesi@cnr.it

AbstractMoisture and salts are the main causes of

decay of porous materials, like wall paintings, stones, plasters and cement-based artefacts. Water is the ‚driving force‘ of decay, such as

SWBSS 2017 – Abstracts

the detachment of the painted layer, the whi-tening of surfaces due to the crystallization of salts (efflorescence), and the weakening of the cementing binder. Early diagnostics of wa-ter content and detection of the presence of soluble salts inside the material is a key issue for understanding the degradation processes in such kind of materials and for improving their schedule maintenance. In this contribu-tion a non-invasive microwave system based on evanescent field dielectrometry is descri-bed. The method was tested in the laboratory on moistened plaster samples, some of them containing salts at different concentrations. Measurements on water-saturated and oven-dry samples provide the basis for calibrating the instrument for on-site measurement of masonry structures, wall paintings and con-crete historical buildings too. The obtained results prove the usefulness of the method as a tool for diagnostics and for monitoring the effectiveness and durability of restoring interventions.

Keywords: sub-surface investigation, mois-ture and salt content, dielectrometry, reso-nant technique, SUSI© system, plaster, stone, concrete.

Determination of the water uptake and drying behavior of masonry using a non- destructive method

A. Stahlbuhk*, M. Niermann and M. SteigerDepartment of Chemistry, University of Hamburg, Inorganic and Applied Chemistry* stahlbuhk@chemie.uni-hamburg.de

Abstract Historic masonry of different types often

suffers from various enrichments in surfa-ce and near-surface areas. Salts, atmosphe-ric pollutants and other materials from ex-ternal sources are possible causes for these enrichments which can directly influence the water uptake and drying of the mason-ry. Thus, a compaction of the superficial po-rous network can be expected in the case of crust formation, an enhanced water upta-ke in the case of hygroscopic salts. Both of these lead to a change of the intrinsic and unaffected water balance. Besides damaging

effects, possibly provoked by crusts, and ele-vated salt contents, it is of interest to inves-tigate how affected walls behave at a given relative humidity, e.g. threshold values for enhanced water uptake or release influen-ced by salts. The present study reports on a non-destructive chamber method used to investigate the impact of encrustations and salts on the masonry’s behavior concerning drying by determining moisture flow. Advan-tages of the chamber are its easy and non-de-structive application on the masonry using a sealing material that is solely pressed on the wall without leaving residues and the use of harmless water vapor. An investigation of wall paintings in the cloister of the St. Peter Cathedral in Schleswig which in parts suffer from massive yellowish encrustations is pre-sented to demonstrate the promising results obtained with the chamber method.

Keywords: non-destructive method, water uptake and drying, encrustations

Measurement of salt solution uptake in fi-red clay brick and identification of solution diffusivity

E. Mizutani1,*, D. Ogura1, T. Ishizaki2, M. Abuku3 and J. Sasaki2

1 Graduate School of Engineering, Kyoto University, Kyoto, Japan

2 Tohoku University of Art and Design, Yamagata, Japan

3 Faculty of Architecture, Kindai University, Higashi- Osaka, Japan

* be.etu@archi.kyoto-u.ac.jp

AbstractSalt solution uptake rates in fired clay brick

were measured with γ-ray to investigate the influence of salt on solution diffusivity for appropriate numerical analysis of salt solu-tion transfer and crystallization in porous materials. NaCl and Na2SO4 are the main salts confirmed in Hagia Sophia (Aya Sophia Museum), Istanbul, Turkey, and are used in this experiment. We identified solution dif-fusivity as a function of solution content by a numerical analysis of solution transfer. The main results are as follows. Solution uptake tests demonstrated that saturated solutions

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take approximately six times longer to attain a steady state than the time needed for pure water to obtain steady state. This was thought to be caused by the viscosity of the dissolved salts and the presence of crystallised salt in the material. We identified solution diffusi-vity by multiplying moisture diffusivity for pure water by a constant to reproduce the measured solution content in the cases where large amounts of efflorescence was observed at the material surface. In the case of a sa-turated solution of Na2SO4, which is conside-red the salt that most frequently precipitates into material, it was necessary to correct the solution diffusivity equation by considering the effect of in-pore salt precipitation.

Keywords: Solution diffusivity, γ-ray attenua-tion, fired clay brick, sodium salts

How surfactants affect salt crystallization in sandstones?

Mohsin Qazi, Daniel Bonn and Noushine ShahidzadehVan der Waals- Zeeman Institute of Physics, University of Amsterdam, The Netherlands

AbstractFor building materials, historic monuments

and statues the crystallization of salts within the porous stones is for a large part respon-sible for their deterioration and breakdown. The most abundant salt on earth, NaCl, is re-cognized as one of the major players in salt damage. It has been shown in recent studies that in confined spaces, NaCl crystallizes only after reaching high supersaturations1, which increases its potential to cause dama-ge by exerting a crystallisation pressure. In order to mitigate the damage, various reme-dies have been tried, one of which includes the use of crystallisation modifiers2,3. Diffe-rent types of additives are known to modify the crystallisation process of NaCl4. Such mo-difiers can also be utilized to change the pat-tern of crystallization but also to control the location of crystal precipitation.

We present both macroscopic and micros-copic experiments assessing the impact of various types of surfactants (cationic, anionic, and non-ionic) on the kinetics of NaCl crystallization during evaporation of

SWBSS 2017 – Abstracts

aqueous salt solutions. We also study the ef-fect of surfactants on the kinetics of drying of salt solutions in sandstones of different porosities . we show the important role of the porosity combined with the nature of surfac-tant on crystallization. The experiments are done under isothermal conditions at two dif-ferent relative humidities representative of summer and winter conditions. Our results show that the addition of small amounts of cationic and non-ionic surfactants drastical-ly change the kinetics of crystal growth. The latter leads to salt crystallization as a thick crust tightly attached to the surface. This is in sharp contrast with pure salt solutions for which the formation of cauliflower-like structures is observed that can easily be re-moved by brushing.4 In addition, these chan-ges to the crystallization process have a si-gnificant impact on the drying kinetics: the evaporation rate strongly decreases when a thick salt crust is formed. Consequently, the porous materials remain wet for longer time; this can subsequently induce other types of damage that are potentially harmful for art-works. Our study shows that although surfac-tants are known to improve the spreading/wetting properties because of their adsorpti-on at interfaces, their use in the conservati-on treatment of stones against salt damage should be done with caution. Depending on the characteristics of the stone, their impact as crystallization modifiers can become more detrimental for salt contaminated porous materials than it is beneficial.

Local strain measurements during water imbibition in tuffeau polluted by gypsum

Mohamed Ahmed Hassine*, Kévin Beck, Xavier Brunetaud and Muzahim Al-MukhtarUniversity of Orleans, INSA-CVL, PRISME – EA4229, France * Mohamed-ahmed.hassine@etu.univ-orleans.fr

Abstract The research presented in this communi-

cation aimed to evaluate the mechanism of spalling generated by mechanical stresses and strains developed due to imbibition and the link with atmospheric pollution genera-ting gypsum in the stone. Tests were carri-

SWBSS 2017 – Abstracts

ed out on a French limestone, called tuffeau. Local strains were measured using strain gage rosettes during water imbibition in polluted and unpolluted samples. Three ro-settes were placed on a sample at different distances from the surface (1, 4, 7 cm) to mea-sure locally the strain during water infiltra-tion. These rosettes determine the strain in three directions 0°/45°/90°.

Results concerning the behaviour of pollu-ted stone during imbibition are compared to unpolluted stone. Results concerning diffe-rential strains between the surface and the core of the stone due to water infiltration de-monstrate unusual behaviour not restricted to expansion alone: a local contraction zone and expansion zone in each direction sepa-rately for the stone. Pollution by gypsum has an effect on the strain measurements mainly on the first few centimetres of the stone.

Keywords: gypsum, spalling, local strain, imbibition, tuffeau

Assessment of the durability of lime ren-ders with Phase Change Material (PCM) ad-ditives against salt crystallization

L. Kyriakou, M. Theodoridou*, and I. IoannouDepartment of Civil and Environmental Engineering, University of Cyprus, Nicosia, Cyprus* mtheodo@ucy.ac.cy

AbstractEnergy consumption in buildings is most-

ly associated with the use of heating and cooling systems. Renders with the addition of Phase Change Materials (PCMs) have the ability to absorb and release thermal energy, when the temperature changes accordingly, thus enhancing the thermal comfort and energy efficiency of buildings. Nevertheless, the performance of such renders with traditi-onal binders lacks international experimen-tal data, especially regarding their durability against salt weathering.

This paper focuses on the effect of different percentages of commercial microencapsula-ted powder PCMs on the properties of hyd-rated and hydraulic lime renders, investiga-ting at the same time the durability of the end-products against salt crystallization. The aim is to produce energy efficient and durable

lime-based renders for the upgrading of con-temporary buildings, as well as for conserva-tion purposes.

The modified composites have significant-ly lower thermal conductivity and increased specific heat capacity at 90 days after labo-ratory production, thus confirming the great potential of PCMs in enhancing the thermal performance of the aforementioned renders. Comparative tests show that the addition of PCMs has an adverse effect on the mecha-nical properties of the renders and a note-worthy reduction of their bulk density. Ne-vertheless, the salt crystallization resistance of the modified renders improves with the percentage of PCM addition, when assessed both quantitatively and qualitatively follo-wing 15 full immersion wetting and drying cycles in Na2SO4 solution.

Keywords: lime, composites, PCMs, salt crys-tallization

Biogenic hydroxyapatite – a new material for conservation.

Andrea Hamilton*, Ronald Turner and Joanna Rens-hawDepartment of Civil and Environmental Engineering, University of Strathclyde, UK* andrea.hamilton@strath.ac.uk

AbstractOrdinary Portland Cement (OPC) is by

weight the world‘s most produced man-made material, and consequently the most used building material. We present for the first time the direct deposition of biogenic hydro- xyapatite onto the surface of OPC, in a syner-gistic process which uses the composition of the cement substrate. The synthesised hydro- xyapatite is very similar to that found in na-ture; having a crystallite size, iron and car-bonate substitution, and a semi-crystalline structure which identify that this biogenic hydroxyapatite is akin to that found in natu-ral bone and tooth enamel. Hydroxyapatites with such a structure are known to be me-chanically stronger and more biocompatible than synthetic or biomimetic hydroxyapatites.

In the built environment, hydroxyapatite coatings have been proposed for the consoli-dation and protection of sculptural materials

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SWBSS 2017 – Abstracts

such as marble and limestone, with biogenic hydroxyapatites having reduced solubility in comparison with synthetic apatites. We further identify that in addition to providing a biofilm scaffold for nucleation, the meta-bolic activity of Pseudomonas fluorescens increases the pH of the growth medium to a suitable level for hydroxyapatite forma-tion. The generated ammonia reacts with phosphate in the growth medium, producing ammonium phosphates, which are a precur-sor to the formation of hydroxyapatite under conditions of ambient temperature and pres-sure. Subsequently, this biogenic deposition process takes place in a simple reaction sys-tem under mild chemical conditions, which are cheap and easy to apply to fragile biologi-cal or architectural surfaces.

Electrode placement during electro-desali-nation of NaCl contaminated sandstone - si-mulating treatment of carved stones

Lisbeth M. Ottosen*, Lovisa C.H. AnderssonDepartment of Civil Engineering, Technical University of Denmark, 2800 Kgs Lyngby, Denmark* LO@byg.dtu.dk

Abstract Carved stone sculptures and ornaments can

be severely damaged by salt induced decay. Often the irregular surfaces are decomposed, and the artwork is lost. The present paper is an experimental investigation on the possi-bility for using electro-desalination for treat-ment of stone with irregular shape with only two electrodes. The used Gotland sandstones were contaminated by NaCl in the laboratory. Due to the relatively good homogeneity in in-itial salt concentration obtained in this way, interpretation of the ED process were direct. Stones with an up-side-down T-shape formed the core of the investigation. Electro-desali-nation experiments were made with diffe-rent duration to follow the progress. Success-ful desalination of the whole stone piece was obtained, showing that also parts not being placed directly between the electrodes were desalinated. This is important in case of salt damaged carved stones, where the most fra-gile parts thus can be desalinated without physically placing electrodes on them. The Cl removal rate was higher in the areas clo-

sest to the electrodes and slowest in the part, which was not placed directly between the electrodes. This is important to incorporate in the monitoring program to decide when a desalination action is finished.

Keywords: Electro-desalination, sandstone, carved stone, NaCl

Salt crystallization effect on the protec-tive treated sandstone by SiO2-based and POSS-based hybrids during hygrothermal cycles

M. J. Jia, L. He*, J. Y. Liang and X. Zhao Department of Chemistry, School of Science, Xi’an Jiao-tong University, Xi’an 710049, China

AbstractThis paper explores the protective perfor-

mance of five hybrids to the sandstone by loading NaCl, Na2SO4 and NaCl-Na2SO4 salt solutions during the thermal-humidity cy-cles. Two SiO2-based hybrids of SiO2-g-PMMA-b-P12FMA and hydrolyzed Me2Si(OMe)2/SiO2, and three POSS-based hybrids of POSS-PM-MA-b-P12FMA, POSS-PMMA-b-P(MA-POSS) and PDMS-b-PMMA-b-P(MA-POSS), are de-signed in our previous researches for stone conservation. The results indicate that the stones treated by five hybrids have obvious salt-resistance. But, due to the different salt crystallization behaviors of the small squa-re crystals formed by NaCl solution and the long tabular prismatic crystals formed by Na2SO4 solution, there is still some salt-de-duced damage confirmed as the order of NaCl-Na2SO4>Na2SO4>NaCl. Comparatively, SiO2-g-PMMA-b-P12FMA has showed the best protective performance without any in NaCl-loaded and Na2SO4-loaded cycles, and only a little mass loss in NaCl-Na2SO4 loaded cycles, followed by hydrolyzed Me2Si(OMe)2/SiO2. However, the treated stones by three POSS-based hybrids only passed NaCl salt cycles, but could not give enough protecti-on in the Na2SO4 and mixed salt cycles. The weathering behavior for untreated stone and treated stone by hydrolyzed Me2Si(OMe)2/SiO2 are inclined to become rough surface in salt crystallization cycle first and then are peeled off the external rock grains layer by layer till

SWBSS 2017 – Abstracts

powder. While the treated stones by POSS-ba-sed hybrids are occurred cracks first and then spread over the whole body. It is possible to suggest that two SiO2-based hybrids perform much better protection than three POSS-ba-sed hybrids.

Keywords: Hybrids; Protective performance; Salt crystallization behavior; Hygrothermal cycles.

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Thursday, 21 September 2017

Studies for conservation issues

Efficiency of laboratory produced water re-pellent treatmets on limestone

C. Charalambous and I. Ioannou*Department of Civil and Environmental Engineering, University of Cyprus, Cyprus* Corresponding author

AbstractA number of cultural and architectural he-

ritage structures all over the world are built with natural stone. Although this material is considered to be one of the most durable geomaterials, many existing stone buildings and monuments show clear evidence of decay and weathering. The deterioration of stone is strongly related to the presence and mo-vement of water within its pore network. Th-erefore, hydrophobic surface treatments are usually adopted to protect existing or new stonework. Such treatments, however, should not affect the breathability of stone; else, the-re is a risk of enhancing possible decay me-chanisms, such as salt crystallization.

Natural limestones appear to have a degree of inherent water repellency. This has been confirmed through multiple measurements of capillary absorption at different tempera-tures, using water and organic liquids. The measurements were carried out on several building and decorative limestones, showing in each case an anomalously low water sorpti-vity. This natural water repellency of limesto-nes was attributed to the presence of organic contaminants, such as fatty acids, in the pore network of the materials under investigation.

In this paper, the natural water repellency of Cypriot limestones is exploited to develop several water repellent surface treatments, based on oleic acid. The aforementioned labo-ratory produced treatments were applied on a Cypriot calcarenite with proven poor dura-bility characteristics. The results suggest that all treatments can permanently reduce the wettability of the stone under investigation, without modifying its composition or appe-arance.

In order to investigate the durability of the treated stone, wetting/drying cycles were per-formed. The results provide strong evidence that treatment with oleic acid positively af-fects the durability of the stone under study. Consequently, the aforementioned surface treatment may be potentially used in practice to protect stone facades in buildings and cul-tural heritage sites.

Keywords: Limestone, Oleic Acid, Water Repellency, Wetting, Drying

Environmental control for mitigating salt deterioration by sodium sulfate on Moto-machi Stone Buddha in Oita prefecture, Japan

K. Kiriyama 1,*, S. Wakiya2, N. Takatori1, D. Ogura1, M. Abuku3 and Y. Kohdzuma2

1 Kyoto University, Japan2 Nara National Research Institute for Cultural

Properties, Japan3 Kindai University, Japan* kiriyama.kyoko.24n@st.kyoto-u.ac.jp

Abstract This study aimed to develop an appropriate

interior environment to mitigate the deteri-oration by sodium sulfate crystallization on Motomachi Stone Buddha in Oita prefecture of Japan. This Stone Buddha is carved on the fragile welded tuff and has been covered by a shelter for the preservation. On this site, salt crystallization, especially in winter, is a ma-jor deterioration factor of this Buddha. In pre-vious studies, the crystallization of sodium sulfate and calcium sulfate were identified by XRD. The temperature and relative humidity were measured both indoor and outdoor. Wa-ter quantity analysis of the groundwater near the Stone Buddha has been conducted revea-ling a higher solute content near the Buddha than in the general groundwater in Japan. According to the temperature and humidity

SWBSS 2017 – Abstracts

measured inside the shelter in winter, it was suggested that the solubility of sodium sulfa-te decreased greatly with dropping in interior temperature and phase change from mirabi-lite to thenardite (sodium sulfate anhydrate) caused the deterioration of the statue. Hence, the shelter was improved to reduce ventila-tion frequency and block the direct solar ra-diation in order to reduce evaporation and decreasing interior temperature in winter. In this study, we have conducted environmental research and salt crystallization experiments under controlled temperature and relative humidity to assess the improvements of the shelter. After improvements of the shelter, the indoor temperature and relative humidi-ty increased in winter. According to our ex-perimental results, the deterioration of the Stone Buddha is reduced highlighting the efficiency of the improvements.

Keywords: Salt Deterioration, Sodium Sulfate, Shelter

Management of sodium sulfate damage to polychrome stone and buildings

David Thickett* and Bethan Stanley English Heritage* david.thickett@english-heritage.org.uk

AbstractEnglish Heritage holds large collections of

polychrome stone. Often the polychromy only remains as small fragments, loosely adhered to the stone surface with any origi-nal binders having converted to oxalate. The sixteenth century limestone Thetford Tomb fragments are amongst the most significant part of the collection. Salt analyses indicated very high concentrations of sodium sulfate present, (up to 1.5% by mass of the stone). Con-sidering the very fragile nature of the remai-ning polychromy and the aggressive nature of this salt, strict preventive conservation is needed to ensure survival of the informati-on. Theoretically, keeping the RH below the thenardite transition line (the RH is tempera-ture dependant) should avoid any damaging salt transitions. Monitoring with acoustic emission in the storage environment, provi-ded a direct tracing of salt transitions. When

plotted against temperature, it became clear that transitions were occurring at between 3 and 7% lower RH than expected from theory. Tests with pure sodium sulfate powder coin-cided with the theoretical values. The most likely reason is the effect of the pore struc-ture, particularly fine pores. The values are consistent for a single piece of stone and vary between pieces. A good correlation was ob-served between acoustic emission events and small pieces appearing on the imaging plate of a prototype particle deposition analyser. Loss of material from two interior building surfaces was monitored using a similar auto-mated camera system. Inspection of the en-vironmental data when material fell, shows similar depression of the RH below the theo-retical values for sodium sulfate.

Keywords: Sodium sulfate, polychromy, acoustic emission, image analysis, preventive conservation

Conservation of marble artifacts by phos- phate treatments: Influence of gypsum con-tamination

E. Sassoni1,*, G. Graziani1, E. Franzoni1, and G. W. Scherer2 1 Dept. of Civil, Chemical, Environmental and Mate-

rials Engineering (DICAM), University of Bologna, Italy

2 Dept. of Civil and Environmental Engineering (CEE), Princeton University, Princeton (NJ), USA

* enrico.sassoni2@unibo.it

AbstractThe use of ammonium phosphate solutions

has proven to be very promising for protec-tion and conservation of marble. However, all the studies carried out so far have been performed on uncontaminated marble. Un-fortunately, this is rarely the case in the field, because marble artifacts exposed outdoors are often affected by sulfation, i.e. formati-on of a gypsum crust on the surface. Because gypsum is much more soluble than calcite, the outcome of the ammonium phosphate treatment is expected to be sensibly alte-red by the presence of gypsum. Therefore, in this study the nature and morphology of the new calcium phosphate phases formed

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SWBSS 2017 – Abstracts

by reacting gypsum with aqueous solutions of diammonium hydrogen phosphate (DAP) were investigated. In particular, the effect of DAP concentration, ethanol addition (aimed at reducing gypsum solubility), and pH were explored. The result is that phase formati-on can be controlled by suitably tuning the above mentioned parameters. Phases with low solubility (such as tricalcium phosphate and hydroxyapatite) can be obtained by in-creasing the ethanol concentration, the DAP concentration or the pH. However, their for-

mation is associated with diffused cracking, likely because of excessive growth of the new phases. Among the investigated formula-tions, treatment with a 0.1 M DAP solution with 30 vol% ethanol at pH=8 seems to be the most suitable one, as it leads to formation of brushite (about 30 times less soluble than gypsum), without cracking, so that a reduc-tion in gypsum solubility in rain is expected.

Keywords: Marble; Gypsum; Black crusts; Hydroxyapatite; Protection

Salt crystallization tests

Salt crystallization tests: Focus on their objective

A. Elena Charola1,*, Inge Rörig-Dalgaard2, Jacek Chwast3 and Jan Elsen3

1 Museum Conservation Institute, Smithsonian Insti-tution, Washington, DC, USA

2 DTU, Department of Civil Engineering, Group of Construction Materials, Lyngby, Denmark

3 KU Leuven, Department of Earth and Environmental Sciences, Leuven, Belgium

* charolaa@si.edu

AbstractMany factors influence the durability of

a building material, such as its mechanical resistance, exposure conditions and the pre-sence of soluble salts in it. Since the latter interact with each other, it is difficult to rela-te any of them to the specific damage obser-ved. Lubelli et al.1 have recently summarized the shortcoming of some salt crystallization tests and of the mathematical models based on the accepted salt crystallization theories. The net result is that there is no single salt crystallization test that can provide all ans-wers since crystallization kinetics, depending on specific circumstances, play a critical role in the induced deterioration. Nonetheless, specific tests have been developed which have proved to be practically viable in as-sessing particular material compatibility or potential damaging sources. Two such tests are described, one using sodium chloride to determine compatibility of restoration mort-ars, and another where the efflorescence of gypsum for brick masonry is evaluated. The-se methods have proven their reliability and

lead to the conclusion that salt tests should be designed for specific objectives.

Keywords: sodium chloride test, sodium sul-fate test, masonry materials, crystallization kinetics

Mitigating salt damage in lime-based mort-ars with mixed-in crystallization modifiers

Sanne J. C. Granneman1, Barbara Lubelli1,* and Rob P. J. van Hees1,2 1 Delft University of Technology, Delft, The Nether-

lands2 TNO Technical Sciences, Delft, The Netherlands*B.Lubelli@tudelft.nl

AbstractThis paper presents the most important re-

sults of a research project which focused on the use of crystallization modifiers mixed in lime mortar to mitigate salt crystallization damage. The research focused on two of the most damaging salts, sodium chloride and sodium sulfate, and suitable crystallization modifiers (sodium ferrocyanide and borax). We report the major findings related to the effectiveness of the modifiers when mixed in the mortar, and the results of characterizati-on of the additivated mortars in comparison with reference mortars. Moreover, the dura-bility of the developed mortars to salt decay is discussed, based on the results of an ac-celerated salt weathering test carried out in laboratory. No major effects of the modifiers on the fresh and hardened mortar properties were observed which might restrain the ap-

SWBSS 2017 – Abstracts

plication of crystallization modifiers in resto-ration mortars. Additionally, the mortars with mixed-in modifiers showed a consider-able improvement of the salt resistance when compared to reference mortars. Considering these results an outlook for future research pathways is given.

Keywords: Crystallization modifiers, self- healing, lime mortar

Artificial decay of rocks for stone treat-ments evaluation in laboratory

Dória Costa National Laboratory for Civil Engineeringdrcosta@lnec.pt

AbstractThe study of conservation treatments on

laboratory requires the use of materials si-milar to those present on the monument. Sampling is always very limited and almost always insufficient to obtain materials to be tested in laboratory. Very often, the use of quarry materials with a different state of al-teration, when compared with those present in the monument, is the common practice.

To obviate this difficulty an alternative is the preparation of specimens using laborato-ry artificially tests “to age” stone materials. Freeze and thaw, crystallization of salts, ther-mal or thermal shock or can be used to ob-tain damaged specimens. The choice depends on the original characteristics of the materi-als and quite often determined by the need to obtain rapid transformation of the materi-al that is available. However, where salts are the proven agent of damage, it seems reaso-nable to recommend that the preparation of these artificially aged samples should be made using the same action that is effective in practice.

Weathered surfaces present on monuments are generally heterogeneous, showing profi-les where the outermost zone is more altered than the inner part. For this reason, the pro-tocol of testing should also be able to provide specimens that can simulate these characte-ristics.

Salt crystallization test has a long tradition of use to access the stone durability to salts. Stone samples are subjected to cycles of im-mersion in a salt solution followed by drying in an oven, using a concentrated solution of

sodium sulphate. It is a very aggressive test, able to produce damage on porous materials, in particular in very porous stones. However, low porosity materials (less than 5% porosity) like granites, are excluded.

The protocol used in this research includes also an “impregnation step” repeated several times before “desalination”. Samples are imp-regnated at 40ºC, placed in a climatic cham-ber (or equivalent) at 5-10ºC for 30-60 minu-tes and then dried at 40ºC, in a ventilated oven, for about 24h. However, the protocol is not universal and must be tested and evalua-ted previously on a non-tested variety.

The test performed on granites used a 10% sodium sulphate solution concentration but other concentrations can be used, depending on the stone type characteristics and its vul-nerability to salt damage.

Physical changes, like porosity, water ab-sorption by capillarity and mechanical re-sistance of the materials were used to cha-racterize and compare the materials after damage. Depending on the type of material (“porous” or “fissured“ type) drilling resistan-ce or ultrasonic pulse velocity are recommen-ded. On fissured rocks, like granites, ultraso-nic methods (“ultrasonic pulsed velocity” - UPV) are considered very sensitive, allowing the detection of salt effect and presence, par-ticularly in laboratory conditions. Drilling resistance used on limestones allows evalua-ting the hardness in depth. The interpretati-on of the profiles must considered the two possible effects; strength increase due to the presence of salt or its decrease due to the da-mage promoted by them, evident after des-alination.

Keywords: salt crystallization test, drilling resistance, ultrasonic pulse velocity, natural stone

First results of the RILEM TC 271 ASC – A review of salt crystallization tests

Barbara Lubelli1,* and RILEM TC 271 ASC working group 1 Delft University of Technology, Delft, The Nether-

lands* B.Lubelli@tudelft.nl

AbstractThe durability of building materials with

respect to salt crystallization is mostly deter- mined by accelerated ageing tests, carried out in the laboratory.

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SWBSS 2017 – Abstracts

An effective laboratory ageing test should assess, in a reliable way and within a rea-sonable period of time, the durability and, especially when the conservation of historic buildings is concerned, the compatibility of a material in practice. However, existing (stan-dard) crystallization test procedures do not generally reproduce solution transport and salt crystallization processes realistically. This may result in damage types that are dif-ferent from those known from practice for the material concerned.

The literature on this subject shows the re-luctance of researchers to use standard tests. The use of different procedures hinders the comparison between the results of different studies. Moreover, none of the existing stan-dards prescribes an objective, quantitative and reliable method for monitoring the da-mage. Another limit of current standard salt crystallization tests consists in the scarce va-lidation of the results from the accelerated test through comparison with field data, for factors such as damage type and severity.1

The RILEM Technical Committee 271 ASC2, initiated in 2016, aims at overcoming the above-mentioned limitations by the develop-ment of improved test procedures for the as-sessment of the behaviour of materials with respect to salt crystallization.

An extensive literature review of laboratory tests is one of the first outcomes of the ongo-ing work of the RILEM TC 271-ASC. The review provides an overview of existing procedures (standard and not) and identifies their advan-tages and limitations.

The following variables are considered in the literature review:- Specimen type, shape, size, number of repli-

cates, etc.- Salt type and amount- Salt contamination procedure- Drying conditions- Methods for the assessment of the damage

and criteria of evaluation of the decayBased on the review, improved ideas are

provided for the development of effective salt crystallization procedures.

References1 B. Lubelli, R.P.J. van Hees, T.G. Nijland, Salt

crystallization damage: How realistic are existing ageing tests? In: Proc. 3rd Int. Conf. Salt Weathering of Buildings and Stone

Sculptures SWBSS 2014 (Ed. H. De Clercq) Brussels: KIK-IRPA, 2014, 259-273.

2 https://www.rilem.net/groupe/271-asc-ac-celerated-laboratory-test-for-the-assess-ment-of-the-durability-of-materials-with-re-spect-to-salt-crystallization-355 (retrieved on September 10, 2017).

Predicting salt damage in practice: A theo-retical insight into laboratory tests

Robert J. Flatt1,*, Nevin Aly Mohamed2, Francesco Caruso3, Hannelore Derluyn4, Julie Desarnaud5, Ro-ald Hayen6, Barbara Lubelli7, Rosa Maria Espinosa Marzal8, Leo Pel9, Carlos Rodriguez-Navarro10, George W. Scherer11, Noushine Shahidzadeh12 and Michael Steiger13

1 ETH Zurich, Switzerland, 2 Suez University, Egypt, 3 University of Oslo, Norway, 4 University of Pau, Fran-ce, 5 The Getty Institute, USA, 6 Royal Institute for Cul-tural Heritage, Belgium, 7 TU Delft, The Netherlands8 University of Illinois at Urbana Champaign, USA, 9 Uni- versity of Eindhoven, The Netherlands, 10 Universtiy of Granada, Spain, 11 Princeton University, 12 Univer-sity of Amsterdam, The Netherlands, 13 University of Hamburg, Germany

AbstractSalt crystallization is accepted to represent

one of the major causes for the degradation of building and ornamental stone. As such, it has attracted the attention of researchers, who over the years have progressively unra-veled most mechanisms involved in salt da-mage. Despite this, many questions subsist about how to quantitatively predict damage or its progression, and in particular how to relate performance on site to that in labora-tory tests.

In this context, a new RILEM TC has been started with the objective of defining labora-tory tests that deliver more reliable predic-tions of field behavior. One deliverable of this TC, is to provide a theoretical insight into this question based on recent progress on the understanding of salt damage. This paper presents a summary of this work, highligh-ting key aspects relating to crystallization pressure, chemo-mechanics and transport. Implications are more specifically discussed in relation to existing accelerated tests in an attempt to better define the type of field ex-posure that they may best represent.

SWBSS 2017 – Abstracts

Friday, 22 September 2017

Studies for conservation issues

Combined non-destructive measurements to understand the salt weathering at the Torre de Quintela, Portugal

Menezes A. Ricardo1,*, Wanja Wedekind2, L. M. O. Sousa3 and Siegfried Siegesmund1 1 Georg-August University Goettingen, Germany2 Applied Conservation Science (ACS) Goettingen/Ber-

lin, Germany3 Universidade de Trás-os-Montes, Vila Real, Portugal*amandamricardo@gmail.com

AbstractThe Middle Age tower in this study is loca-

ted in a small village in the region of Quinte-la, north of Portugal, from which the tower also receives its name. This building is part of a simple agricultural area near the Alvão Mountains that has been standing since the 11th Century. The Quintela Tower exhibits a prismatic format with dimensions of 8.6 m x 10.5 m x 18 m and is built from different types of granite. The interior is divided into three floors.

Three main types of granites are used on the façade of this building, and they can be classified as leucocratic, phaneritic, in-equigranular, with subhedral crystals and grain sizes varying from coarse, medium to fine. The most common weathering forms are efflorescence, back-weathering, coloring, fractures and biological colonization.

The main cause for the back-weathering evident on the Quintela Tower might be rela-ted to the behavior of salts crystallizing near and under the surface of the granites. Crys-tallization of a supersaturated solution can provide sufficient crystallization pressure to cause several ruptures on the stones.

To understand the state of decay by salt weathering, combined non-destructive mea-surements and acquisitions were applied. The measuring procedure consisted of three measurements from the same point in the middle of the stone blocks, using a simple moisture measuring device of the brand GE Portimeter. The open porosity was checked by measuring the water uptake using test-pi-

pes. The different granite lithotypes as well as the damages were mapped and quantified.

This measuring equipment allows the moisture level to be determined by measu-ring the capacity, the dry conductivity and the wet conductivity. For the first two measu-rements the equipment is placed against the surface of the ashlar. For wet conductivity, however, sterilized cotton pads are used and moisturized with 5 ml of distilled water. They are then placed on the stone blocks for thirty seconds and the conductivity measured over the pad.

In total 1,355 measurements were taken on the tower. Outside the tower 728 measure-ments were obtained (182 per each one of the four sides) up to the same maximum reacha-ble level, and inside 627 were done, where 375 were taken on the first floor, 132 on the se-cond floor and 120 on the third and last floor.

Generally, conductivity is higher when the wet cotton pads are used and shows so-metimes different results comparing to the dry performed measurements. This can be traced back to soluble but not hygroscopic salts. Moreover, the measurements show dif-ferent results according to the orientation of the four façades of the tower. This can be tra-ced back to, not only the main wind and rain direction, but also to the sun incident angle and the environmental conditions (moisture) throughout the years and other features dis-cussed in this study.

Keywords: Non-destructive measurements, salt weathering, Torre de Quintela

Protecting Pompeii with clay barriers

Martin Michette1 and Ralf Kilian2

1 University of Oxford, School of Geography, UK2 Fraunhofer-Institut für Bauphysik, Valley, Germany

AbstractThe project will identify local soils from the

Pompeii region for use in protecting the ar-chaeological sites from ground moisture. Sui-

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SWBSS 2017 – Abstracts

table soils will be subject to laboratory expe-rimentation and modified if necessary, with the aim of installing a barrier in a pilot-test in Pompeii and undertaking long-term monito-ring of the effects. The aim of the project is to explore the potential of naturally occurring clayey soils for mitigating moisture intrusion and salt contamination of built heritage.

The risk of ground moisture at historic buildings can leave architects and conserva-tors facing a difficult decision. Standardised vertical or horizontal moisture barriers re-quire chemical or mechanical intervention with the fabric, whilst leaving the building unprotected can lead to salt contamination and rapid deterioration. Clay barriers present a possible alternative. The technique is com-monplace in some areas of environmental engineering, and has recently re-emerged in built heritage conservation. Specialised mix-tures, generally bentonite modified soils, as well as naturally occurring clayey soils have been employed; these can be compacted at the foot of below ground masonry without the need for further fixation. The method re-lies on various hydraulic mechanisms, which can differ depending on the soil or mixture being used.

Naturally occurring or slightly modified so-ils were traditionally used for protecting buil-dings in a number of vernacular techniques. Work carried out at the FH Potsdam in 2014 included an investigation of Saxonian Till, which was occasionally used as a barrier in local building until the 18th Century. The-re is evidence of other lime-rich soils being used historically in a similar fashion else-where. A high stability appears to be a key factor for materials used as vertical barriers against variable moisture loads, in order to avoid fracture during dry-periods.

The archaeological sites at Pompeii are par-ticularly at risk from ground moisture due to saturation and seepage after heavy rainfall. Recent work has identified that local volcanic earth was used as a plaster, in part to pro-tect walls against moisture, possibly even in the form of vertical barriers. There are sug-gestions that volcanic soils may be generally suitable for use as clay liners. Investigations of this historic local building material will form the initial stage of the project. Besides developing a field protocol for assessing po-

tential soils, the project will include in depth laboratory analyses and hygrothermal mo-delling, as well as the installation and mo-nitoring of a barrier at a suitable location in late 2017.

Keywords: Clay Barrier; Pompeii; Heritage Conservation

How not to bother soluble salts while grouting

C. Pasian1,*, F. Piqué2, C. Riminesi3 and A. Jornet2 1 Department of Conservation and Built Heritage,

Faculty for the Built Environment, University of Malta, Msida, Malta

2 Institute Materials and Constructions, University of Applied Sciences and Arts of Southern Switzerland, Lugano, Switzerland

3 Institute for the Conservation and Valorization of the Cultural Heritage (ICVBC), National Research Council, Florence, Italy

*chiara.pasian@um.edu.mt

AbstractThe objective of this research work was

to assess if the injection of water-reduced grouts (water-ethanol-based) mobilises so-luble salts to a lesser extent compared to the injection of conventional water-based grouts. Ethanol was used as a partial substitute for water in grouts preparation, being a poorer solvent for soluble salts when compared to water. Three injection grouts were evaluated; for each grout individually, the performance of mixtures prepared with 100% water was compared to the performance of the same grout prepared with water-ethanol. To assess the different performance in a salt loaded system, the grouts were tested into replicas of delaminated plaster intentionally conta-minated with NaCl. The salt movement was followed by evanescent field dielectromet-ry using the SUSI© instrument. Grouts with reduced water content were also tested on site, at the San Vincenzo Oratory in Pazzal-lo, Tessin (CH), on decorated plasters afflicted by severe delamination associated with high amounts of soluble salts. Two adjoining areas, comparable in condition and in salt content, were stabilised with the same grout differing only in the nature of the suspension medi-

SWBSS 2017 – Abstracts

um used (water-ethanol vs. water). Both in the laboratory and on site, it was experimen-tally verified that water-ethanol-based grouts caused a significant reduction of salts mo-bilisation, bothering salts to a lower extent compared to a typical water-based grouting intervention.

Keywords: injection grouting, water, alcohol, dielectrometry, SUSI©

Early treatments for porous plaster and salt- damaged wall decorations in Scandinavia

Herman Andersson1, Isabelle Brajer2, Mads Chr. Christensen2,* and Poul Klenz Larsen2,+1 Konservator Herman Andersson AB; Tollarp, Sweden2 National Museum of Denmark; Kongens Lyngby,

Denmark* mads.christian.christensen@natmus.dk and + poul.klenz.larsen@natmus.dk

AbstractTreatment of salt damage on wall paintings

and stone monuments by means of barium compounds and oxalates came much into fo-cus in the last third of the 20th century.

This paper draws attention to the early use of barium compounds and oxalates for con-solidation of wall paintings and plaster in Scandinavia. In 1900, a Danish patent was is-sued for a treatment using oxalate solutions to consolidate plaster. In another early case from the 1940s, barium chloride was used on two wall paintings in Sweden to immobilize highly soluble sodium sulphate salts by che-mical treatment, producing insoluble barium sulphate.

In Copenhagen, chemical methods for con-solidation of friable porous materials were a major focus of research in the 19th century. A museum with a richly decorated façade of coloured plaster was built in 1839-1848 to house the sculptor Bertel Thorvaldsen’s works. The façade decoration showed signs of weathering barely 20 years after completion. This instigated the launching of an extensi-ve research project, which lasted with inter-ruptions about five decades, during which various treatment methods were developed. Among them were successful experiments using solutions of magnesium fluorosilicate (fluat) and ammonium oxalate to cure the de-

teriorated porous coloured plaster. These ex-periments influenced the treatment of wall paintings in medieval churches.

Perusing early 20th century memos and correspondence between chemists and con-servators discussing the use of barium chlo-ride and fluat it is remarkable that they are not particularly focused on soluble salts and salt damage. It seems as if they felt that a consolidation of friable and porous surfa-ces was sufficient treatment to prevent salts from reaching the surface and causing dama-ge. Other initiatives, such as implementing climate control, were rarely considered.

In Denmark the focus was primarily on the creation of barriers, but in Sweden methods of immobilizing salts through chemical reac-tions were tried. In 1941-46 newly uncover-ed medieval wall paintings in Finja, which were extensively damaged with sulphates were impregnated with an excess of barium chloride on the entire decoration. Thus, the sulphate problem was solved, as insoluble barium sulphate was formed. Unfortunately, there emerged other salt-related problems, including those caused by highly soluble so-dium chloride as well as barium nitrate, the by-product of excess treatment with barium chloride. Knowledge of such historical treat-ments is imperative for the implementation of correct conservation treatments today.

Keywords: Consolidation, barium salts, fluat, oxalates, salt damage

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Conservation issues and salt reduction

The application of hydroxyapatite-based treatments to salt-bearing porous limesto-nes: A study on sodium sulphate-contami-nated Lecce Stone

Gabriela Graziani1,2,*, Enrico Sassoni1, George. W. Scherer3 and Elisa Franzoni1

1 Department of Civil, Chemical, Environmental and Materials Engineering (DICAM), University of Bologna, Italy

2 Laboratory of NanoBiotechnology (NaBi), Rizzoli Orthopaedic Institute, Bologna, Italy

3 Department of Civil and Environmental Enginee-ring (CEE), Princeton University, Princeton (NJ), USA

* gabriela.graziani2@unibo.it

AbstractSalt weathering is among the most severe

phenomena affecting porous limestone, of-ten leading to the loss of precious material from historical sculptures and building faça-des. Together with exerting a weathering action, salts can also hamper the success of consolidation treatments, by interfering with consolidants’ penetration and/or curing re-actions. On site, application of consolidants on non-contaminated stone is rarely feasible, especially in the case of porous limestones; for this reason, testing application of consoli-dants on salt laden stone is of particular rele-vance to guarantee their successful applicati-on in the field.

In this paper, two hydroxyapatite (HAP)- based treatments have been applied to Lecce Stone, a very porous organogenic limestone, highly susceptible to salt weathering. The two treatments differ for DAP concentration, application procedure and presence/absence of ethanol in the formulation. Prior to trea-ting, specimens were subjected to salt crys-tallization cycles in a sodium sulphate solu-tion, to cause salt contamination and induce weathering. They were then desalinated, pur-posely leaving a percentage of salts in the stone (SO4

2- after desalination ~ 0.15-0.3wt%). Phase formation and distribution as a result of different contamination levels were inves-tigated, and the efficacy of the treatments in comparison to ethyl silicate was determined, as it is currently the most used consolidant for this lithotype. Finally, the durability of

the most promising treatment to further salt crystallization was evaluated, again in com-parison with ethyl silicate.

Promising results were obtained, as the presence of sodium sulphate did not prevent the HAP- based consolidants from uniformly distributing in the stone, sealing cracks and forming insoluble phosphate phases. Inte-restingly, the application on non-desalina-ted stone revealed that the nature and the amount of the phases that form as a result of the treatment are dependent on the amount of salts in the stone. Finally, most promising HAP-based formulation was found to enhance the stone’s durability towards further salt crystallization, also compared to ethyl silicate.

Keywords: salt weathering, cultural heritage, calcium phosphates, limestone

Moisture transport during poultice application

Christoph Franzen1,*, Martin Aulitzky2 and Stephan Pfefferkorn2

1 Institut für Diagnostik und Konservierung an Denkmalen in Sachsen und Sachsen-Anhalt e. V., Dresden, Germany

2 Hochschule für Technik und Wirtschaft Dresden, Fakultät Bauingenieurwesen/Architektur, Dresden, Germany

*franzen@idk-denkmal.de

AbstractWater movement is the key parameter in

poultice application for desalination. Water is the eluent and transport medium for the salts to be extracted from the porous subs-trate. While from the hypothetical point of view the dynamical processes of water in-gress, dissolution of salts, transportation and precipitation seems to be well known, mea-sured data on the water quantities at specific stages of the process are scarce. Especially, time approximations about the change in main movement direction of the water are unidentified. By experimental data we give indications to the total amount of water used with different poultice compositions and the development of the water ratio during the

SWBSS 2017 – Abstracts

process until equilibrium dryness is reached. In conclusion we suggest increasing the ra-tio of water and probably the poultice layer thickness from cycle to cycle to increase the effective cross section stepwise.

Keywords: desalination, water movement, salt transport, poultice material

Evaluation of desalination and restoration methods applied in Petra (Jordan)

Wanja Wedekind* and Helge Fischer Applied Conservation Science (ACS), Goettingen/Berlin, Germany* wwedekind@gmx.de

AbstractOne of the major causes for the deteriora-

tion of historical monuments made up of sandstones can be attributed to the circula-tion and evaporation of salt laden fluids per-colating through the rock material, an aspect that has been either overlooked or neglected in previous restoration attempts, often with damaging consequences. Particularly the lack of consideration for the importance of a quantitative analysis of the salt content of the rock, has led to adverse effects in subse-quent restoration attempts.

In the course of restoration of antique tombs no. 825 and 826 in the world heritage site of Petra the role of salt in the weathering process was fully taken into account and the restoration process executed accordingly.

With regard to the desalination two diffe-rent methods were applied: the poultice me-thod and the sprinkling method. The degree of desalination was in both cases intermit-tently measured until the concentration of the rock was evaluated to be low enough to initiate the restoration process with applica-tion of the selected restoration mortar. Its condition was then probed by long term suc-cessive inspections.

This study discusses the results and limits of both procedures and the techniques and methods applied in the course of the restora-tion of the two monuments.

Keywords: Petra, sandstone, salt weathering, desalination procedures, restoration mortar, restoration procedures, control of success

Desalination of Cotta type Elbe sandstone with adapted poultices: Optimization of poultice mixtures and application terms

Julia Maitschke1 and Heiner Siedel2,* 1 University of Applied Sciences Potsdam, Dept. of

Conservation and Restoration, Potsdam, Germany2 TU Dresden, Institute of Geotechnical Engineering,

Dresden, Germany* Heiner.Siedel@tu-dresden.de

AbstractCotta type Elbe sandstone has been fre-

quently used as construction material and ornamental stone on buildings over centu-ries. Desalination of this sandstone (often performed with cellulose poultices in resto-ration practice) is ineffective in many cases due to its high amount of fine pores.

A mixture of cellulose, kaolin and sand (1:2:1 by weight, CKS_121) with a high por-tion of fine pores was applied for poultice desalination on artificially salt-loaded spe-cimens of Cotta type sandstone. Moreover, another mixture of the same components (CKS_128 with cellulose-kaolin-sand 1:2:8 by weight) and two poultices that are frequent-ly used in restoration practice (ready-made Rajasil (RAJ) poultice and Arbocel® CC1000/BWW40 (ARB) mixture) were applied for com-parison. The pore size distributions and the structures of all poultices were characterized by MIP. The results showed highest amounts of extracted salt for the poultices with clay and higher portions of sand (CKS_128, RAJ). The CKS_121 poultice, although fitting best with regard to pore size distribution, shows high shrinkage due to the high amount of kaolin, which leads to loss of adhesion to the substrate during the desalination process. The results clearly demonstrate that in des-alination practice of stones with fine pores compromises have to be found between the competitive parameters of “ideal” pore struc-ture and low shrinkage of the poultice, both influenced by clay contents in the mixture.

Keywords: salt reduction, desalination, Cotta type Elbe sandstone, poultice mixtures

32 33

Salt reduction and case studies

Salt extraction by poulticing in the archaeo-logical site of Coudenberg

Sebastiaan Godts*, Roald Hayen and Hilde De ClercqRoyal Institute for Cultural Heritage, Belgium (KIK-IRPA)*sebastiaan.godts@kikirpa.be

AbstractA common method for the extraction of

salts is the use of poultice materials. Despi-te extensive scientific research, the salt ex-traction process in practice often remains empiric. This paper aims to further the un-derstanding of a salt extraction by poulti-cing in practical experiments. Three types of poultice materials are tested on brick ma-sonry in 12 different locations in the subter-ranean archaeological site of Coudenberg in Brussels. The tested poultice materials have different compositions including kaolin clay, sand and/or cellulose fibres, theoretically favouring advection and/or diffusion. It is shown that for an accurate interpretation of the results it is crucial to evaluate the salt content in the poultice and to a depth of at least 20 cm in the different materials of the substrate, while considering the different densities and surface area of each material. Furthermore, it is shown that the presence of gypsum overshadows the results, hence the exclusion of equimolair contents of Ca2+ and SO42- is essential for the evaluation. Finally, the results of these experiments reveal that regardless of the different procedures, such as, the poultice type, pre-wetting or applicati-on time, salts are being redistributed into the wall rather than extracted.

Keywords: salt extraction, desalination, poul-tice, historic masonry, archaeological site

Tracing back the origins of sodium sulfate formation on limestone as a consequence of a cleaning campaign: the case study on Cha-rité and Espérance sculptures of Chartres cathedral

Benkhalifa Sara1, Vergès-Belmin Véronique2,*, Rolland Olivier3 and Leroux Lise2

1 Conservatrice – restauratrice de sculptures2 Laboratoire de Recherche des Monuments Histo-

riques, CRC-LRMH-CNRS USR 3224 3 Conservateur – restaurateur de sculptures* veronique.verges-belmin@culture.gouv.fr

AbstractIn 2012, five years after cleaning by Mora

paste, sodium sulfate related deterioration was noticed on two XVIIIth century limes-tone sculptures of Chartres cathedral. This paper presents the results of the diagnostic study and of the conservation intervention performed on these sculptures, with a focus on trials to determine the salt phases res-ponsible for their deterioration. The metho-dology chosen includes mineralogical and chemical analyses of samples collected on the sculptures during the diagnostic phase and after kaolin-based poultice desalination (XRD, quantification of soluble salts, SEM-EDS), but also mineralogical analyses of the salts extracted from the poultices.

Mora paste chemicals (and in particular EDTA disodium salt) are probably responsible for the quick deterioration of the sculptures through complex and unidentified chemical pathways: at least two of the mineral phases found in this case study are not present in the JCPDS data base on mineral phases. It is proposed to set up an inventory of unidenti-fied phases found in case studies similar to this one, in order to gather the knowledge spread in different institutions, and later to build scientific projects on the topic of ED-TA-related deterioration.

Keywords: thenardite, EDTA, Mora, AB57, cleaning, desalination, limestone

SWBSS 2017 – Abstracts SWBSS 2017 – Abstracts

Granite and schist masonry desalination by poultices at Jacobine Church in Morlaix, France

Barbara Brunet-Imbault*, Benjamin Reidiboym and Clément GuinamardStudiolo: engineering office for cultural heritage conservation and restoration* barbara.brunet@cabinet-studiolo.com

AbstractThe Jacobine Church of Morlaix in France

has been deconsecrated in the XIXth cen-tury. Afterwards, it has been used as a sta-ble and then turned into a market which included salt storage for food preservation. Moreover, the church is built downhill of a significant slope next to the Jarlot river. The church, built with granite and schist, pre-sents important salt resurgences, granular disintegrations and moisture areas on joint mortars. The project of the city is to resto-re the church and turn it into an exhibition space included in a new museum. According to this project, the architects want to apply new lime plasters on the walls, which is not possible because of the high levels of salts. In order to evaluate the salt contamination, samples have been taken in different heights and depths in stones and mortars. Contami-nation profiles have been obtained and poul-tices based on cellulose fibers, clays and fine quartz sand have been formulated. Stone and poultice porosimetries have been measured in order to adjust the poultice formulation. The goal of this adjustment was to obtain the appropriate pore size distributions to impro-ve the moisture transport mechanisms bet-ween stones and poultices. Three poultices formulations containing variable ratios of cellulose, sand and clays have been selected. Test areas included join removal as much as possible and vacuum cleaning of the wall surface before the first poultice application. These on-site trials allowed us to study des-alination efficiency, including poultice for-mulation and desalination practice (number of poultices applications, wall surface preli-minary preparation). Granite cut stone and schist blocks masonries have distinct proper-ties, so desalination practice must be adjus-ted to obtain an optimized efficiency, inclu-ding a different poultice formulation and a

different masonry preparation. Nevertheless, the desalination of such contaminated ma-sonries is a challenge to preserve lime plaster from future degradations.

Keywords: desalination, practice, poultice, efficiency

Investigation of salts sources at the Karad-jordje‘s Gate on the Belgrade fortress

Maja Franković1,*, Nevenka Novaković2, Suzana Erić3, Predag Vulić3 and Vesna Matović3

1 Central Institute for Conservation in Belgrade, Belgrade, Serbia,

2 Cultural Heritage Preservation Institute of Belgrade, Belgrade, Serbia

3 University of Belgrade, Faculty of Mining and Geo-logy, Belgrade, Serbia

* maja.frankovic@cik.org.rs

AbstractThe Karadjordje’s gate is a monument of

culture, part of the historical complex of the Belgrade Fortress. The gate, dated from 1740 to 1791, is made of autochthonous limesto-ne of Miocene age. After years of exposure to environmental conditions and different anthropogenic influences, the stone blocks showed a wide range of decay forms. The gate was subject to a restoration campaign in 2007 using cement based materials. To-day, the gate shows renewed signs of degra-dation: detachment of “artificial stone” used for restoration; scaling and disaggregation of the original stone blocks. Salts efflorescence is present around the joints of stone blocks in the upper part of the gate and under the reconstructed rosettes.

Characterization of salts was carried out by SEM-EDS and XRPD analyses. Results showed the presence of the following salts: syngeni-te, gypsum, thenardite, darapskite, bassanite, niter, aphthitalite and witzkeite. The paper concludes that there is an influence of resto-ration materials to salt contamination and to the decay of stone and “artificial stone”.

Keywords: limestone, salt, restoration mate-rials, decay

34 35

Salt content of dust and its impact on the wall paintings of the church St. Georg at the UNESCO World Heritage site Monastic Island of Reichenau in Germany

Jürgen Frick*, Manuela Reichert and Harald GarrechtMaterials Testing Institute, University of Stuttgart, Germany* juergen.frick@mpa.uni-stuttgart.de

AbstractSt. Georg is one of the three Romanesque

churches on the island of Reichenau at Lake Constance, Germany, built between the 9th and 11th century. UNESCO inscribed the mo-nastic island of Reichenau in the World Heri-tage List in 2000. St. Georg has meticulously restored wall paintings which are exposed to a very humid indoor environment. An-thropogenic risks and preventive mitigation measures to reduce the environmental stress were identified within a research project. One aspect of research was the impact of salt in dust collected from time to time from dif-ferent areas in the nave and the crypt. The paper identifies possible sources and ana-lyses the harmfulness in relation to the in-door climate by salt mixture simulation with ECOS/RUNSALT. The data were compared with drilling samples of walls and passive dust sampling data. An experimental analy-sis by dynamic vapour sorption (DVS) of dust samples is planned in near future.

Keywords: Salts in dust, climate assessment, DVS, source identification, salt mixture ana-lysis by ECOS/RUNSALT

Investigation and examination of a degraded Egyptian painted limestone relief from Tell Hebua (Sinai)

Eid Mertah1,*, Moamen Othman2, Mohamed Abdel-rahman3, Mohamed Fatoh4 and S. Connor5 1 Conservator of archaeological materials, Conserva-

tion Centre, Egyptian Museum of Cairo, Ministry of Antiquities, Egypt

2 Director of conservation Centre, Egyptian Museum of Cairo, Ministry of Antiquities, Egypt

3 Director of Scientific Research, Projects Sector, Mi-nistry of Antiquities, Egypt

4 Chief of stone Conservators, Conservation Depart-ment, Egyptian Museum of Cairo, Ministry of An-tiquities, Egypt

5 Research Fellow at The Metropolitan Museum of Art, New York.

* eid.mertah@yahoo.com

AbstractThis paper presents a study bas-relief from

the New Kingdom (1550-1070 BC), which was found in Sinai in 2009 and came the Egyp-tian Museum, Cairo, in a quite challenging condition. The interest of this piece lies in the danger that the salt causes to the block’s surface, and particularly to the pigments of its decoration. The block is sculpted on two opposite sides, which both need to be conso-lidated, in order to be safely displayed in the museum’s galleries. The authors describe the investigation carried out to identify the types of salts and to select the possible techniques to remove them and preserve the surface and pigments.

Keywords: limestone relief, Sinai, salt weathe-ring, crystallized salts, stabilization

Salt-induced flaking of wall paintings at the Mogao Grottoes, China

Lori Wong1,*, Su Bomin2, Wang Xiaowei2, Amarilli Rava3 and Neville Agnew1

1 The Getty Conservation Institute, USA2 Dunhuang Academy, Mogao Grottoes, Dunhuang,

Gansu, China3 The Courtauld Institute of Art, UK* lwong@getty.edu

AbstractThe Mogao Grottoes, a World Heritage Site

in northwest China, is known for its surviving 492 painted Buddhist cave temples. Commis-sioned over a thousand year period, from the fourth to the fourteenth centuries, the ca-ves were hewn into a 1.6 km long cliff face and the wall paintings executed on earthen plasters. Situated in a remote and arid desert landscape, these painted caves have endured throughout the centuries but many have also suffered from salt-related deterioration.

Repeat cycles of treatment for flaking on salt-damaged wall paintings have caused worsening of conditions resulting in signifi-cant loss of painted plaster. A research pro-ject to study this intractable problem and to develop and implement improved treatment methods was undertaken as part of a colla-boration between the Getty Conservation

SWBSS 2017 – Abstracts SWBSS 2017 – Abstracts

Institute (GCI) and the Dunhuang Academy (DA) under China’s State Administration for Cultural Heritage (SACH).

This case study looks at the activation me-chanisms and deterioration processes of salt-induced flaking and highlights the de-velopment and implementation of remedial and preventive measures to prevent further loss from occurring. Topics investigated in-clude the material composition of the pain-tings and plaster, previous treatments, salt identification and distribution, environmen-tal conditions and the impact of increased humidity. Results show that past treatment of flaking wall painting with polyvinyl alco-hol (PVA) and polyvinyl acetate (PVAc) created a film-like barrier that reduced permeability and trapped salts below the painted surfa-ce. This led to a build up of salts that when exposed to periods of high humidity caused disruption and powdering of the plaster from cycles of deliquescence and crystallization; the consolidated upper layer, then separated and lifted, in a new form of flaking, referred to as exfoliation.

The study also aimed to improve me-thods of condition monitoring to better as-sess when change due to salt activity occurs and to implement findings from the Visitor Carrying Capacity Study for the site. This in-cluded identifying caves at risk of salt-related deterioration and closing them to visitation during periods of high humidity.

Keywords: Mogao Grottoes, Dunhuang, wall painting, flaking, salt deterioration, previous treatment

Investigation and conservation concept of salt damaged epitaphs in the church of Werben (Saxony-Anhalt)

Steffen Laue*, Dörte Poerschke and Benjamin HübnerDepartment of Conservation and Restoration, Uni-versity of Applied Sciences Potsdam, Germany*st.laue@fh-potsdam.de

AbstractThe case study of the St. Johannis church

in Werben (Saxony-Anhalt) is one of those instances where conservators and restorers working in the field of building heritage have to find sustainable solutions for a cultural he-ritage site affected by high humidity levels and salt content for centuries. In the church of Werben, the ground floor of the steeple houses a remarkable collection of predomi-nantly polychrome epitaphs from the 16th – 18th centuries. These epitaphs reflect in an unique way the story of important citizens of Werben and provide an extensive overview of the design and techniques used in the manufacturing of such monuments through various epochs. During an inventory of the epitaphs, several damages were attributed to salts and the high moisture content in the ground floor of the steeple. Salt analyses, cli-mate measurements and calculations with the computer model ECOS/RUNSALT were used to understand the damage processes of the epitaphs. The results provide the basis for applying appropriate conservation methods and materials pertaining to the room and the polychromic epitaphs. As a case study one epitaph was removed and preserved in the workshop of the conservation and resto-ration department in Potsdam.

Keywords: Werben, polychromic epitaph, salt damage, climate, ECOS/RUNSALT, conservati-on concept

36 37

SWBSS 2017 – Posters

Posters

P1 Deicing Salts: An Overview E. Charola, C. Bläuer & B. Rousset (Washington, DC, US)

P2 Technique for transportation of stone sculptures damaged by salt crystallisation V. Marinković (Split, Croatia)

P3 Investigation of the preservation of salt damage about the Buddha statue carved into the cliff by controlling the room temperature and humidity in the shelter N. Takatori, D. Ogura, S. Wakiya, M. Abuku, K. Kiriyama & Y. Kohdzuma (Kyoto, Japan)

P4 Investigation of post-restoration salt weathering at the mosaics of Dafni Monastery, Greece A. Stefanis, P. Prokos, E. Ftikou & P. Theoulakis (Athens, Greece)

P5 Dampness problems in renovation plasters shortly after intervention: The case of a historic building in the Old Town of Prague C. Nunes, O. Skružná & J. Válek (Prague, Czech Republic)

P6 Development of a network-based climate monitoring system for climate assessment and regulation C. Leonhardt, S. Leonhardt, J. Heller & D. Hoffmeister (Kiel, Germany)

P7 Pathology of old and repair mortars after exposure to salts M. Stefanidou (Thessaloniki, Greece)

P8 The stone reliefs of Großjena – problems of deterioration and approaches for a salt reduction in a long term J. Meinhardt, T. Arnold, K. Böhm & B. Hübner (Potsdam, Germany)

P9 Measurement of hysteresis in sorption isotherm of porous materials with sodium salts (Na2SO4, NaNO3, NaCl) E. Mizutani, D. Ogura, T. Ishizaki, M. Abuku & J. Sasaki (Kyoto, Japan)

P10 SalzWiki/Saltwiki – Two Specialized Wikis on “Salt Decay” H.-J. Schwarz & A. Weyer

SWBSS 2017 – Posters

Deicing Salts: An Overview

A. Elena Charola1,*, Bénédicte Rousset2 and Christine Bläuer2

1 Museum Conservation Institute, Smithsonian Insti-tution, Washington, D.C., USA

2 CSC Sàrl, Conservation Science Consulting, Fri-bourg, Switzerland

* charolaa@si.edu

AbstractThe world production of salt (NaCl) was

over two hundred million tons in 2015. The US is the second larger producer of salt af-ter China, produced over four million tons of which 43% were consumed in highway deicing. While NaCl is the most commonly used salt, other salts are added to it to im-prove its performance, such as CaCl2, MgCl2. To reduce the use of the deteriorating NaCl, other salts are also used, such as magnesium acetate, calcium magnesium acetate or potas-sium and magnesium formate. The addition of sand and other inorganic insoluble com-pounds to aid in making surfaces less slip-pery is discussed, as well as the recent use of organic deicers and the problems that these can induce.

The paper aims to present an overview of deicing salts, and the differences with an-ti-icing or antifreeze solutions. It also dis-cusses the problems they induce to vehicles, buildings and constructions, while also con-sidering the negative aspect they have for the environment as well as their contribution to air pollution. Some examples are presented to illustrate the problem and less aggressive alternatives are discussed, especially with re-gard to the conservation of valuable architec-tural heritage.

Keywords: deicing salts, building deterioration, environmental pollution

Technique for Transportation of Stone Sculptures Damaged by Salt Crystallization

Vinka MarinkovićCroatian Conservation Institute, Split, Croatia* vmarinkovic@h-r-z.hr

AbstractThe paper presents a technique for hand-

ling and transportation of stone sculptures damaged by salt crystallization. A limestone

sculpture from the Cathedral of St. Lawrence in Trogir was studied and pre-consolidated with cyclododecane. First, test were perfor-med in the lab. On 5 glass slides were applied powder of the Seget stone and then consoli-dated with 50% solution of CCD in Shellsol T, 50% solution of CCD in white spirit, 50% solution of CCD in toluene, with holt melted CCD and hot melted CCD with cotton gauze. After the tests were performed, a technique of pre-consolidation with melted cyclodo-decane and facing tissue was used in situ on the sculpture. Practical uses of the technique were considered in the paper.

Keywords: cyclododecane, stone, pre-consoli-dation, salts

Numerical analysis on salt damage suppres-sion of the Buddha statue carved into the cliff by controlling the room temperature and humidity in the shelter

Nobumitsu Takatori1,*, Daisuke Ogura1, Soichiro Wa-kiya2, Masaru Abuku3, Kyoko Kiriyama4 and Yohsei Kohdzuma2

1 Department of Architecture and Architectural Engineering, Kyoto University, Kyoto, Japan

2 National Institutes for Cultural Heritage Nara National Research Institute for Cultural Properties, Nara, Japan

3 Faculty of Architecture, Kindai University, Osaka, Japan

4 Graduate School of Advanced Integrated Studies in Human Survivability, Kyoto University, Kyoto, Japan

* takatori.nobumitsu.62a@st.kyoto-u.ac.jp

AbstractMotomachi Sekibutsu is a Buddha statue

that was carved into a cliff in Oita City, Ja-pan, during the 11th or 12th century. It was designated as a national historic site in 1934. The stone statue is constantly affected by the penetration of heat and moisture into the cliff, and concerns have been raised about its deterioration. Various preservation measures have been taken to prevent this; however, the main cause of deterioration, salt damage, has not been eliminated. Here we develop a nu-merical analysis model to calculate the heat and moisture behaviour in the statue and its shelter. Using this model, we reproduce the shelter’s hygrothermal environment before and after renovation and evaluate it with re-spect to damage caused by sodium sulphate.

38 39

Our results show that the improvement in airtightness drastically contributes to decrea-sing the evaporation from the statue and suppressing the salt phase change; thus, the renovation of the shelter suppressed sodium sulphate salt damage to the statue.

Keywords: Conservation environment, Ar-chitectural environment, Coupled heat and moisture transfer, Sodium sulphate, Phase change

Investigation of post-restoration salt we-athering at the mosaics of Dafni Monastery, Greece

Alexis Stefanis1, Petros Prokos2, Ekaterini Ftikou2 and Panagiotis Theoulakis1

1 Technological Educational Institute of Athens, Department of Conservation of Antiquities and Works of Art, Athens, Greece

2 Ministry of Culture, Directorate of Conservation of Ancient and Modern Monuments, Athens, Greece

* astefanis@teiath.gr

AbstractDafni is an 11th century Byzantine monas-

tery in the suburbs of Athens and a UNESCO World Heritage Site. The main church of the monastery is a cross-in-square of the octago-nal type building, housing the best preser-ved complex of wall mosaics from the early Komnenian period (ca. 1100AD). The building has suffered many structural problems, espe-cially by the 1999 Athens earthquake and a great restoration programme was initiated in 2000. The poor state of the building has significantly affected the mosaics. The main problem were the structural damages of the budling fabric that allowed moisture infiltra-tion, triggering a series of decaying pheno-mena, such as cracking and detachments re-ducing the preservation state of the mosaics. It is important to mention that salt weathe-ring was not observed before conservation interventions.

Apart from the structural reinforcement of the building, restoration works also aimed to protect the interior of the building from water penetration. After the completion of restoration and conservation works in 2016, the mosaics presented soluble salt efflore-scences and consequent disaggregation of a specific type of tesserae produced from mar-

ly limestone. A methodology was developed in order to investigate the pathology of the mosaics and study the weathering mechanis-ms. The approach was based on non destruc-tive testing techniques (NDT’s) such as Infra red Thermo (IRT), Ground Penetrating Radar (GPR) combined with microclimatic monito-ring and on instrumental techniques such as Optical Microscopy, Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy, X-ray Diffraction, and Mercury Intrusion Porosimentry.

Results obtained from the examination of the mosaics by means of the IR-Thermo technique suggest existence of areas on the surface of the mosaics suffering from high moisture content combined, in some cases, with biological decay. Data collected from the 2D profiles of the GPR network scattering, re-veal the structural integrity of the mosaics substrates since no large voids and disconti-nuities in the medium were detected.

Microscopic observation showed that the marly limestone tesserae were completely disintegrated as opposed to neighboring tesserae and mortar joints, which were not affected at all. Chemical and mineralogical analyses indicate that damaged areas presen-ted high concentrations of calcium and mag-nesium sulphates, probably originating from previous conservation mortars and by the building material itself. The environmental conditions did not favour frequent crystalli-sation cycles.

Data correlation from NDT and laboratory analyses, suggests that weathering is a re-sult of water retainment within the mason-ry and differences in porosity and pore size distribution of the mortar and the varieties of stone tesserae. Depending on the microcli-matic conditions, aqueous solutions evapo-rate through the marly limestone triggering salt weathering mechanisms. Furthermore, in this work, the importance of treatment evaluation and post-treatment monitoring is highlighted.

Keywords: Dafni monastery, mosaics, salt decay, investigation

SWBSS 2017 – Posters

Dampness problems in renovation plasters shortly after intervention: The case of a his-toric building in the Old Town of Prague

Cristiana Nunes*, Olga Skružná and Jan VálekInstitute of Theoretical and Applied Mechanics, Prague* nunes@itam.cas.cz

AbstractThis work is focused on the analysis of

moisture and soluble salts affecting a histo-ric building in the Old Town of Prague that was subject to a recent rehabilitation inter-vention. The intervention included the injec-tion of a chemical damp-proofing substance at the ground level for blocking rising damp and the application of renovation mortar co-ats (in accordance with WTA-2-9-04/D) up to 2-3m of the walls’ height and of a lime-ba-sed mortar in the area above. Striking wides-pread moisture stains appeared six months after the intervention, mostly on the lime-ba-sed mortar coats. To assess the effectiveness of the damp-proofing barrier applied in blo-cking rising damp, an assessment campaign was carried by collecting several samples of the renovation mortar coats, as well as of the underlying historic masonry materials along a vertical profile. The samples were analysed with the hygroscopic moisture content me-thod combined with ion chromatography to investigate the nature and amount of salts present. Nitrates were generally found in high content at high levels in the walls pointing out a historic accumulation by rising damp as their most probable source. The plastering strategy implemented, i.e. with a water-repel-lent system applied at the lower level and an absorptive lime-based mortar coat applied at the upper level, can have contributed to draw more moisture (and salt) to a higher level. The overall results obtained indicate that ri-sing damp was reduced to some extent, the moisture present in the superficial layers being mostly due to hygroscopic adsorption and the moisture registered in the deeper levels corresponding to previously accumula-ted damp before the intervention.

Keywords: soluble salts, rising damp, hygros-copicity, moisture content, deliquescence

Development of a network-based climate monitoring system for climate assessment and regulation

Christian Leonhardt*, Sabine Leonhardt, Julika HellerWerkstatt für Kunst und Denkmalpflege* intonaco@gmx.de

AbstractIn the cloister (the so-called Schwahl) of

the St. Petri Cathedral in the German town of Schleswig, the current situation of the his-torical wall paintings was investigated in the context of a research project funded by the German Federal Foundation for the Environ-ment (German: “Deutscher Bund für Umwelt” – DBU). The project is focused on the investi-gation of the intense salt contamination and its connections with the climatic situation.

In this context, a network-based climate monitoring system was installed and tested in 2016. The data is accessible online, which is more convenient and advantageous than conventional data logger records for long-term climate measurement and evaluation, which can only be accessed in situ. It allows direct response to critical climatic values by connected alarm, control and regulation sys-tems. This way, measurements can be taken promptly thus preventing damage and high restoration costs. Previously, climatic data had been collected in the course of the rese-arch project since 2007, the comprehensive evaluation of which served as a basis for the setting of the parameters for the new system.

Measurement data are transferred directly to an open-source based server infrastruc-ture, which is scalable and ready for future requirements. Due to the data being direct-ly available on the internet, it is possible to provide a minute-accurate climate monito-ring in real-time. Thus, the evaluation of an arbitrary number of measurement locations and the analysis of local causes (events, we-ather changes) can be put into practice.

The system was conceived and tested for the requirements of the Schleswig Cathedral. It can also be used in archives, depots and churches and thus constitutes a reliable basis for climate monitoring.

Keywords: Climate monitoring, climate data, networking-based monitoring, preventive conservation, regulation systems

SWBSS 2017 – Posters

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SWBSS 2017 – Posters

Pathology of old and repair mortars after exposure to salts

Maria StefanidouCivil Engineering Department, Aristotle University of Thessaloniki, Greece stefan@civil.auth.gr

AbstractThe influence of salts on the durability and

serviceability of building materials has occu-pied many researchers for many decades in a scientific basis. The sources and mechanis-ms by which salts penetrate and crystalline, were an extensive subject of research. The complexity and the amount of the parame-ters that can act synergistically on the poro-us nature of masonry materials, renders the study of the topic rather difficult. Neverthe-less, old mortars, from different monuments, after many centuries of exposure in different environments, have been studied in terms of salt content and their mechanical, structural and physical properties have been recorded. Approaches to connect those properties in order to result on the effect of the salts on their durability have been made. The correla-tions are not always easy and the conclusions can be rather blurred. Going a step further, compatible mortars made of traditional bin-ders such as lime, natural pozzolan and brick dust have been produced. Under controlled conditions, the samples were subjected to salt cycles. The problematic of recording the pathology arose as mainly qualitative cha-racteristics (optical observation assisted by microscopes), rather than weight measure-ments could be performed. By this way the most often met situations are summarized under the following situation:1. The salts were mixed randomly in the matrix2. The salts were identified in the binder-

aggregate interface 3. The salts are crystallized in accessible voids

in the binder system 4. The salts were detected on the surface

Also, exfoliation, cracks and loose parts were observed at different stages of the acce-lerated salt tests based on the different bin-ders used. The purpose of the salts crystalli-zation tests is to predict the resistance of the materials exposed to the action of the salts, as well as the determination of a time ratio between the laboratory test and a real situa-tion. An effective decay test should simulate reliably in laboratory conditions and in a

relatively short period of actual behavior of materials. The accelerated salt tests seem to need reconsideration in order to use them for recording the real pathology caused to mortars.

Keywords: old mortars, repair mortars, salt tests, methods, pathology

The stone reliefs of Großjena – problems of deterioration and approaches for a salt reduction in a long term

Jeannine Meinhardt1, Torsten Arnold2, Karsten Böhm2 and Benjamin Hübner1

1 Department for Conservation and Restoration, Uni-versity of Applied Sciences Potsdam, Germany

2 Landesamt für Denkmalpflege und Archäologie Sachsen-Anhalt, Halle, Germany

* meinhardt@fh-potsdam.de

AbstractThe rock carvings of the baroque Steinerne

Album consist of 12 reliefs of biblical motifs concerning viniculture. In their entirety, the-se are the biggest stones reliefs of the Euro-pean cultural area. The outcrop, where the reliefs were carved out of, represents diffe-rent varieties of a Triassic Sandstone, mainly siliceous bounded. Depending on the variety, clay-rich horizons and carbonatic cement are also common. The type of cement, clay-con-tent and porosity have significant influence on the weathering resistance of the material. As a result of harmful environmental influ-ences massive damage processes, caused by Sulphur oxide emissions, were initiated on the reliefs. Also the unprotected exposition and especially direct connection to the be-drock boosted the damage progress. The seri-ously affected stone album was comprehensi-vely restored between 1997-1999. The reliefs were treated with Ethylsilicates (KSE) using the infusion method. Furthermore, stone replacement mortars were applied. Measures in the context of salt reduction were not car-ried out. This is precisely where the research project starts. After the restoration, a mo-nitoring and care concept was established. Among other things, the main task of the monitoring is the control and repair of the applied mortars and visual strength-testing, possibly combined with retreatment. Soon after restoration, strong sanding and flaking in combination with massive efflorescences were observed on some of the reliefs. Repair

SWBSS 2017 – Posters

mortars repeatedly delaminate. The deteri-oration proceeds quite quickly. The monito-ring care concept that has been agreed upon needs to be reviewed. In the current research project, the potential of a long term salt re-duction in form of weathering resistant poul-tice mortars is to be tested. So, the reaction front of salt crystallisation is shifted from the carved surface into the poultices and salts are reduced from the stone. New approach of the project is the salt reduction as a long term care measure while at the same time the carved surface is still recognisable. In this context, a special requirement is on the application of the poultice materials in order to avoid a significant morphological impact on the reliefs. Main focus in the project is on the adaption of poultice mortars formu-lations on the characteristics of the different stone varieties (e.g. porosity). The variable decay status of the stones at small-scall in-fluences the procedure of mortar application and it requires adaption of adhaesive tensile strength parameters.

Using wireless, minimally invasive sensors, the actual reservoir of soluble components in the depth profile and their migration depen-ding on moisture penetration in the bedrock and the climate are currently being monito-red. So, the potential of salt transport from depth towards the surface can be assessed realistically.

Measurement of hysteresis in sorption iso-therm of porous materials with sodium salts (Na2SO4, NaNO3, NaCl)

Etsuko Mizutani1,*, Daisuke Ogura1, T. Ishizaki2, Ma-saru Abuku3 and J. Sasaki2

1 Graduate School of Engineering, Kyoto University, Kyoto, Japan

2 Tohoku University of Art and Design, Yamagata, Japan

3 Faculty of Architecture, Kindai University, Higashi- Osaka, Japan

* be.etu@archi.kyoto-u.ac.jp

AbstractSalts exist in the liquid or solid phases in

porous materials, and both phases signifi-cantly influence the moisture diffusivity and the sorption isotherm of materials. It is well known that many porous materials show hysteresis in the sorption isotherm, which demonstrates that the equilibrium moisture

content during the desorption process is lar-ger than that during the adsorption process, provided the relative humidity is the same. In this research, we investigated the influ-ence of three types of sodium salts (sodium sulfate, sodium nitrate, and sodium chloride) on the hysteresis of the sorption isotherm. These are salts that are confirmed to be in the bricks at archeologically significant sites such as the Hagia Sopia in Instanbul. The re-sults indicated that the equilibrium moisture content of autoclaved aerated concrete loa-ded with different amounts of single sodium salts varied during the desorption process.

Keywords: sorption isotherm, hysteresis, so-dium salts, ALC

SalzWiki/Saltwiki – Two Specialized Wikis on “Salt Decay”

Hans-Jürgen Schwarz1,* and Angela Weyer2,+1 Ri-Con/Research in Conservation, Hannover, Ger-

many2 HAWK University of Applied Sciences and Arts Hildes-

heim/Holzminden/Göttingen, Hornemann Institute, Hildesheim, Germany

* hans-juergen.schwarz@ri-con.de+ weyer@hornemann-institut.de

AbstractThe German- and English specialist wikis

on salt decay offer free of charge a lot of qua-lity information about salts, salt damage and measures for salt damage. Currently the 500 Wiki pages written by renowned experts are very often frequented by researchers and practitioners; the high access figures indicate the need for and the quality of the articles. The bibliography lists more than 2200 titles.

Since the DFG (Deutsche Forschungs- gemeinschaft) project ended, the Hornemann Institute of the HAWK has been hosting the wikis while the newly founded association SIK e. V. (Salze im Kulturgut – Forschung, Praxis, Wissenstransfer) has been updating the con-tent.

If you would like to use this worldwide in-formation platform free of charge as an au-thor or if you want to support the quality management as an editor, please contact us.

www.salzwiki.de; www.saltwiki.net

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SWBSS 2017 – Conference Dinner

Conference Dinner – 21 September 2017, 19:30

The Conference Dinner takes place in the Meierei in Potsdam located in the New Garden of Potsdam.From the city center (e. g. Platz der Einheit) please take the bus No. 603 til the last station: Höhenstraße. Then go back 100 m and you will see the entrance to the park New Garden and the Meierei. At night, the last buses go back to town at 9:52 pm and 10:52 pm (or 30 minutes walk to city center).

Mit dem Bus Linie 603 bis Endstation (Höhenstraße)

Mit dem PKWFolgen Sie den Hinweisschildern „Cecilienhof“ und fahren die Straße „Am Neuen Garten“ bis zur Einfahrt PKW-Parkplatz „Meierei/Cecilien-hof“.

Brauerei • Meierei im Neuen Garten • GmbHIm Neuen Garten 10 • 14469 PotsdamTel.: 0331/7043211 • Fax: 0331/7043213www.meierei-potsdam.de