F7-.--

in ltructural Engineering and Construction

VOLUME 1

Y.M. XIE a I. PATNAIKUNI - EDITORS

(A JqvJg, & Francis\_/, rayror d rrancrs uroup

PROCEEDINGS OF THE FOURTH INTERNATIONAL STRUCTURAL ENGINEERING ANDcoNSTRUCTTON CONFERENCE (rSEC-4), MELBOURNE, AUSTRALtA,26-28 SEpTEMBER,2007

Innovations in StructuralEngineering and Construction

\-OLUME 1

Edired by

\.\'1. Xie & I. PatnaikuniI\ I I T [Jniv ersity, Mel b ourn e, Au s trali a

O JqvJgt & Francis\/ rayror&Francrsuroup

LONDON i LEIDEN / NEW YORK / PHILADELPHIA / SINCAPORE

Taylor & Francis is an imprint of the Taylor & Francis Group, an informa business

O 2008 Taylor & Francis Group, London, UK

Typeset by Charon Tec Ltd (A Macmillan Company), Chennai, IndiaPrinted and bound in Great Britain by TJ International Ltd, padstow comwall

A11 rights reserved. No part of this publication or the information contained herein may be reproducedstored in a.retrieval system, or transmitted in any form or by any -"aor, .l."ironic, mect ani"al ;t -photocopying, recording or otherwise, without written prioi peimission from the publisher.

Although all care is taken to ensure integrity and the quality ofthis publication and the information herein,no responsibility is assumed by the publishers nor theiuthor for any damage to the property orpersons as a result of operation or use ofthis publication and/or the inform'ation contained herein.

Published by: Taylor & Francis/BalkemaP.O. Box 44i,2300 AK Leiden, The Netherlandse-mail: Pub.Nl@tandf.co.ukwww.taylorandfrancis.co.uk/engineering, www.crcpress. com

ISBN Set: 978-0-415-457 55_2

ISBN Volume I : 97 8-0-41 5-457 54-5ISBN Volume 2: 978-0-415-45756-9

Table of contents

heface

-{ctnouledgements

Leri€g'ers

Crmminees

\OLL:N{E 1

ianote papers

Ib drivers and issues shaping the construction sectorfi- F.lwugan

C-slmea-r- and structure - the benefit of the third dimension!G-1. Carfme

eadryoent of new construction materials for structural useY t,,wbishnan

'ffhc problems with current risk management practices: How to overcome themfr(. trrnlemore

$olxrulral rEsponse as an aspect offire safety ofbuildingsi.fr. Ifonrrs

]Drtgn fa sustainable development of concrete constructionI*t srrfi!'

furution structural des ign

hlrul rchirecture and its implications for structural engineeringI. .fi.floxgft- S. Ihtning & J. Plume

na;frcuU bcreen parametric associative and strucfural softwareJd- (oadrs

fti@c lErEration using evolutionary algorithms(. #tfr".- F. kheurer K. Bollinger & M. Grohmann

!a@ c,ryrtenzed multi-disciplinary design environment for building structurestfraillm &l.M.Xie

lllnrGnl d csqruction of a retaining wall constructed from soil-bagstr hmo&S.rn

lnnovations in structural Engineering and construction - xie & patnaikuni (eds)@ 2008 Taylor & Francis Group, London, 1SBN 978-0-415-4SiSS_2

xxIXxIII

xxvXXVT

l3

t9

29

39

5't

63

69

75

8l

Two -eeneral methods for creating tensegrity structures oftowers, arches, bridges and stadium roofs 87Y. Zhou.1.\1. -\-ie & X. Huang

-\n trurovatile Design/Build Frame (DBF) concept study - seismic design of mid-rise residential/officebuilding rvtth reinforced concrete ductile moment frames integrated with prefab modules1 l -K. Chang & B.N. Liu

\llSr modular deployable shelter system concept and analysis techniqueT. Ontar, G. Van Erp, T Aravinthan & P Key

Curragh train load-out: Innovative design for short construction periodsD.T Turner

Steel structures

S-N curves for thin CHS-CHS T-joints under in-plane bending using the hot spot stress method 1 13ER. Mashiri & X-L. Zhao

Study on blind-bolted split tee connections to concrete-filled steel tubes for steelmoment-frame buildings 119H. Yao. H.M. Goldsworthv & E.E Gad

Investigation on basic and optimum COF of frame structures using fishbone-shaped modelY.G. Zhao & WC. Pu

Corrosion and fatigue behaviors of steel plates at the boundary with concrete

93

99

105

t27

135 i

I.T. Kim, S. Kainuma & N. Hosomi

Damage assessment of MR steel-frames with a simple criterion based on stiffness deterioration 141H. Moharrami & H. Madani

Steel plate pre-stressing reinforcement for notched steel girder endsM. Sakano, K. Matsumoto & H. Namiki

Ultimate siip behavior of double-lined perfobond rib connectorM. Himukai, K. Fujii, K. Fukada &Y. Doukan

Development and validation of a simple approach to model aerodynamic loads on a militaryjet intake structureG. Chen, R. Boykett & K. Walker

The design of portal frames using cold-formed channel sections: A comparison of Australian,US and European requirementsD.T Vyden & J.E. Mills

147

155

VI

Finite element modelling of steel lattice tower legs reinforced for increased loadsC. Tongkasame, J. Mills &Y. Zhuge

Elastic-plastic local stability and load-carrying capacrty of steel membersP. Juhds

Experiments on ultimate bending strength of corroded thin cylindrical shellsK Hashimoto, T. Kondoh, H. Nakamura & K. Fujii

A new approach to design and modeling of flexible corrugated steel plate shucturesunder constructionL Janusz & O. Kaplirishi

Bidges and special structures

Sructural art in arch bridge design in CroatiaI Radit, A. Mandit & A. Kindij

Ertigue in concrete decks of cable supported bridgesP-K Singh

Ib usage of glued laminated timber structures in architectureL Kilar & S. Vratuia

E&cts of hear,y truck load on medium span bridge girders^Y. Zou, A. Saber &W Alaywan

Cmsruction project management of large concrete arch bridges in Croatia2 Zaerit,l. Kindij & J. Radit

htrluation and rehabilitation of concrete bridges in USAA *ni*ongse

Ih rt of reftofitting historic arch bridges.f l(orros

flikss bridges: Current practice and research in ChinaZ? Un- W Lin & D.W Peng

C*tete and masonry structures

"t*rin'and critical comparison of the provisions for the anchorage of tensile reinforcementr fmican" European and Australian Standards,'X GIturl

tmed earth and concrete wall system for sustainable housing.& ha&arr. T. Molyneaux &J. Novotny

hl fuigue response of latex modified reinforced concrete beamsDr W. Lt. Gupta & u.B. Choubey

Ld precast concrete in Melbourne, Australiar,r &rfus

205

199

213

219

227

233

237

245

2st

2s9

26s

2'71

279

287

293

VII

301

.I

Structural behaviour of fuC cylindrical panel with gable wal1T. Hara & N. Hashimoto

Behavior of concrete prism after high temperature under cyclic reversed loadingG.L. YLtan A Q.T. Li

Performance-based optimization of strut-and-tie models in reinforced concrete deep beams

Q.Q. Liang &A.WM. Ng

Study on R/C member subjected to torsion and axial forceH. Tsukuda, T. Shigematu & T. Tamura

Development of a semi-fabricated composite system for floor slab constructionWA. Thanoon, M.S. Jaafar & J. Noorzaei

Minimum reinforcement and fiber contribution in tunnel linings: The Italian experienceB. Chiaia, A.P Fantilli & P Vallini

Precast concrete residential applications in the United StatesC.J Perry

Experimental determination ofenergy absorption capacity for prestressed concrete sleepersunder impact loadsA.M. Remennikov & S. Kaewunruen

Use offault tree analysis in risk assessment ofreinforced concrete bridges exposed toaggressive environmentsIll Zhtr, S. Setunge, R. Gravina & S. Venkatesan

Intemal temperature rise and early thermal stresses in concreteB.M. Abbas & R.S. Al Mahaidi

Development of a simple and low cost shear connector for minimizing tripping hazards ofpedestrian concrete pavementsllC. Koay, Y.M. Xie & S. Setunge

Behaviour of fibre reinforced concrete slabsM.N.S. Hadi

307

3ls

321

Reliability ofbond measuring devices in pretensioned prestressed concrete 333I.R.A. Weerasekera. A. Sabesh & R.E. Loov

Corewall and outriggers as lateral system for the Peak at Sudirman JakartaD. Sukamta

Experimental investigation on the behavior of RC flat plat structure with nonrectangular columns 345W Liu & C. Huang

An investigation ofthe application of spun-cast prestressed steel fiber reinforced concrete poles 353S. Zhao. R. Gao & X. Li

339

327

3s9

365

387

37t

Strengthening of shear damaged RC beams with external clamping 375T. G. Suntharavadivel & T Aravinthan

38t

395

401

VIII

40'/

I

Ltperimental work on reinforced and prestressed concrete deep beams with various web openingsT.\1. Yoo, J.H. Doh, H. Guan & S. Fragomeni

Shear crack width of concrete member under axial load and transverse reversed cvclic loadT Tsubaki & M. Dragoi

Snrdv on the fracture behavior ofthe R/C member covered by acrylic resin and random staple glassSiber mattingI Tamura, M. Tokuda, T Kadonaga & T. Yamamoto

Rebabilitation of non-ductile RC moment-resisting frames with poor beam-column joints! C fiang & K. Hsu

$ear strength of steel fibre reinforced prestressed concrete beamP-P Ltagsford, N. Lloyd & PK. Sarker

rr,s. esimation of slip strength of perfobond rib connector considered with concrete confinements{" Fz.iii. Il. Himukai, H. Iwasaki &Y. Dokan

Dewrrrive factors causing deterioration of paints on buildings wallsL W:niotaite

C oa,s mt c ti o n m at e r i al s

Fret md restrained shrinkage behaviours of OPC and slag concretes with admixedAmhr':rtPlene fibresT.t' .ti J.G. Sanjayan & FG. Collins

$cf.-roropacting concrete for direct finish structuresL ,frfolr,: L" Bodnarova, D. Henkl, O. Fiala, T. Klecka & K. Kolar

*,at mited self compacting lightweight concretesX. fiirfu & ll. Hubertova

t f,urq. .r tk durability of porous concrete using slag-gypsum cementf 0fim,a,:rra, J. \akamoto, K. Amo & K. Yokoi

{tnMrE!{tn: rariabilify of input parameters for calculation of autogenous shrinkage of hardeningffiYIEP

.,ffi ff-}il ;trz der Ham, E.A.B. Koenders & K. van Breugel

fuqr m fu deselopment of medium strength self-compacting concrete using fly ashI -tuuir & S-flandal

i"ry rr .ir-:n reqrrncl'dielectric spectoscopy for monitoring cement hydration kinetics,L ffirlrl:c G lland:uka & D. Koroiak

h-rgtt afmorrar containing activated slag0-t il,&on" T.C]r- ]Ioh'neaux, I. Patnaikuni & D. Law

$clctury f'v m optimal technical solution and concrete mixture for erosion prevention in,h ciiifuL"

il. .fi,lrumyfo- lI. lflikoi. I. Planinc & J. Suiteriii

4t3

421

43s

441

44'7

427

455

463

471

477

483

489

497

501

505

Ix

509

Using semantic blogging to support knowledge management in construction industry 1557D. Xue, C. Wang & I.T Hawryszkiewycz

Application of favorableness - reality index in evaluation of organization performance,case study: Implementation plan of quality management system 1565M. Ahmadinejad, J. Ayoubinejad, M. Maghrebi & G. Ghahremani

Assessing the readiness of construction quality assessment systems (CONQUAS) deplolnnentwithin UK construction organisations 1571N. Chileshe &YL. Sim

Indoor air quality related to building performance and productivity 1579I. Senitkova, M. Bucakova & J. Zacharova

Author index I 585

:

l

l

l

l

I

i

i

ij

I

I

I

iII

I

-Jb

xx

lnnovations in Structural Engineering and Construction - Xie & patnaikuni (eds)@ 2008 Taylor & Francis Group, London, ISBN 978-0-415-4S7SS-2

R.elie\r,ers

lfiE E^t'tors gratefully acknowledge the contributions made by the following people who reviewed the technicalmors lld provided valuable comments and recommendations.

"tmnx. \lohajerani4rom. Bukou'ski.+u,nmru Sb4anrurmci Seaouciq,ftla-: Chanq,un ]Jiu:cnflmr-m Smgtrqcnom:n DeeksOm,rurur Bhanacha{ee{rylr TrmEr[iE S,{t

hrm Ei*eenilnrurlme Qianh Fraogopolh'rc cr&ri&rnc C.umichaelIh'u L.lr&qm DroilskiIlhilf R-Mofrmo Lqi'fm t[;iehftfu"(e$rrtatinirumr Mrshnif,Iruloo Bmtmpill. lbalmi. ,\nrndeiuotrTmilm

Gerhard GirmscheidGreg SchofieldHong GuanIan GilbertIngrid SenitkovaJay SanjayanJohn BuckeridgeJohn ChristianJohn-Paris PantouvakisJohn WilsonKamal GautamKazem GhabraieMei-Yung LeungMark BoulonMark LutherMartin LoosemoreMarton MarosszekyMohamed ElchalakaniMohan KumaraswamyMuhammad HadiMumtaz UsmenNelson LamNick BlismasNick HaritosPramod SinghPhillip DunstonQing Li

Ravi RavindrarajahRebecca GravinaRichard EckhausRichard FellowsRon WakefieldSai-On CheungSam FragomeniSaman de SilvaSarah ZhangScott SmithSri VenkatesanStephen LiangSujeeva SetungeSwapan SahaSyedAhmedTakahiro TamuraTakashi HaraTom MolyneauxXiangyuWangXiaoLingZhaoXiaodong HuangXueqing ZhangYew Chin KoayYong-Lin PiZhigar.gXiao

xxv

lnnovations in Structural Engineering and Construction - Xie & Patnaikuni (eds)@ 2008 Taylor & Francis Group, London, ISBN 978-0-415-45755-2

Committees

&C Executive Committee

fmjit Singh, Chair, University of Hawaii, USAHYazdani, Secretary North Dakota State University, USAh*rrhrrsh31 Patnaikuni, RMIT University, Australia&hi Hara, Tokuyama College of Technology, Japanho Bontempi, University of Rome, ItalyIldm Dinevski, University of Maribor, Slovenia

bnional Scienffic and Technical Committee

mr Xie, Chair, RMIT University, Melbourne, AustraliaElrhrhan Patnaikuni, Co-chair, RMIT University, Melbourne, AustraliaqEa Ahed Florida International University, USAiha Aoua{ Salford University, UKNAditi, Illinois Institute ofTechnology, USAtrr Baldwin, The Hong Kong Polyechnic University, Chinah4f Bhattacha{ee, Indian Institute ofTechnology Delhi, Indiaho nmempi, University of Rome "La Sapienza", Italyn BahNr, University Joseph Fourier, FrancetbCrria| University of Pavia, Italyh(LChrmg; City Universiry Hongkongbftislm, University of New Brunswick, Canada

fr:Oirsti, University of Maribor, SlovenialhFlscEr, University of Port Elizabeth, SouthAfricahHbws, University of Hong Kong, Chinah[rr;ryot, University of Colorado at Boulder, USAblEilrrt tlniversity of New South Wales, AustraliaqHemcheid, Swiss Federal Inst. ofTech, Switzerland|h fE,Tokuyama College of Technology, Japanb.HL King Fahd Univ of Petroleum & Minerals, Saudi Arabia

bhh. I qn:rr {hfyslsify, USAtrIG, The Nelson Mandela Metropolitan University, South Africa

University of Hong Kong, ChinaLlniversity of Strathclyde, UK

hnakis, National Technical University ofAthens, GreeceH- Sonh Dakota School of Mines, USA

Souh East Universiry China[frnrErsity of Western Sydney, Australia

Techical University of Kosice, Slovakiatlniv€rsity of Qataq Qatar

UErusityofHawaii, USAhas Hindu University, India

f*rtt| hrrdue University, USAlJhriy of Hong Kong, China

ffireld Hallam University, UKIbkqrama College of Technology, Japan

University, USAIfdrcrnty, Netherlands

XXVT

Mumtaz Usmen, Wayne State University, USAXiangyu Wang, The University of Sydney, AustraliaSun Wei, South East University, Nanjing, ChinaFrankYazdani, North Dakota State University, USAXueqing Zhang,Hong Kong University of Science and Technology, China

Local Scientific and Technical Committee

Mike Xie, Chair, RMIT University, MelbourneIndubhushan Patnaikuni, Co-chair, RMIT University, MelbourneDavid Carmichael, University of New South Wales, SydneyAndrew Deeks, University of Western Australia, PerthRichard Eckhaus, Barry Gale Engineers, MelbourneSam Fragomeni, Victoria University, MelbourneEmad Gad, Swinburne University of Technology, MelbourneNick Haritos, Melbourne University, MelbourneMartin Loosemore, University of New South Wa1es, SydneyMarton Marosszeky, University of New South Wales, SydneyVijay Rangan, Curtin University ofTechnology, PerthRavi Ravindraraj ah, University of Technology, SydneyJay Sanjayan, Monash University, MelbourneGreg Schofield, Greg Schofield & Associates Pty Ltd MelbourneAhmad Shayan, Australian Road Research Board, MelbourneGeoff Taplin, Maunsell, MelbourneJohn Wilson, Swinburne University of Techrology, Melbourne

Local Organising Committee

Mike Xie. Chair. RMIT UniversityIndubhushan Patnaikuni, Co-chair, RMIT UniversityNick Blismas, RMIT UniversityJohn Buckeridge, RMIT UniversitySaman de Silva. RMIT UniversityRebecca Cravina. RMIT UniversityTom Molyneaux. RMIT UniversitySujeeva Setunge. RMIT UniversityRon Wakefield, RMIT University

XXVIII

lnnovations in structural Engineering and construction - xie & patnaikuni (eds)@ 2008 Taylor & Francis Group, London, 1SBN 978-O-4l 5-45755-2

.::ength of mortar containing activated slag

" :. -\dam, T.C.K. Molyneaux, I. Patnaikuni & D. Law. L'niversity, Melbourne, Victoria, Australia

: - R\CT: The strength development of Portland cement mortar, blended cement-slag mortars and alkali. :d slag (AAS) mortars was investigated. Variables were the level of slag replacement in the blended

-. , :-slag mortars, and activator concentration and alkali modulus (AM) in the AAS mortar. In addition the,-':'iheatcuringonAASmortarswasalsoinvestigated.Mortarspreparedusingalkaliactivatedslagasbinder- -::3ter early strength than ordinary Portland cement mortar and blended cement-slag mortars of the same:-"rrnder ratio. A1l AAS mortars gained strength more rapidly at heat curing however at later age the heat

" -- ::duced the ultimate strength compared to normal curing specimens.

.,RODUCTION

' :rental concern related to the production ofr : - . .n terms of energy consumption and emis-, -

- O: is driving the search for more sustainable' , ..iernatives. One of those alternative materials*. .iitious/binder using industrial by-products.i . :: ofthe industrial by-products which is fre-L -:ed as cement replacement material. Blended' .' r .'ement and ground granulated blast-furnace

,,, :tsS) has been used for many years to improverrL L .-. of concrete. Research shows that with suit-t' .:: r;ation, high level of slag replacement can

, : :.rr structures where chemical resistance tor : ,:lorides, and sea-water is needed (OsborneI -. rs.ever, under normal curing condition," : - ,:fleflt slag gain strength more slowly than

. : -:ment mortars for the same water cementr :' ,-,ett et a1. 2006).

" -'-:nace slag is a latent hydraulic materialiilr . - :3act directly with wateq but it requires an' ,rd alkali released from the hydration of',lr'" . - -::rent, i.e. Ca(OH)2 is a suitable activator.rr' -: .,.hen used with Portland cement slag willu, .. " --3Ct until some Portland cement hydrationilL .. '' - lce. This delay causes blended Portlandilirrrr r .: slag to developed strength more s1ow1yrr , - .: lhan Portland cement alone (Gjorv 1989,llr, -.-r.-\lkaliactivationofslagisanewmethod'r 1r :. of granulated blast-furnace slag based'qi L r " r rr ith alkalis other than released from$lfin,r',1, . -:r 3rrt. such as; caustic alkalis, silicate salts,uttiti r ::te salts of weak acids (Bakharev et al.iM\ - .989, Talling 1989).

r '. ;eScribed here forms part of a research

resistance ofreinforced concrete using fly ash and slagwith different 1eve1s ofactivation (i.e. latent hydraulicmaterial, alkali activated cementitious matenal. andgeopolymer).

In order to compare the strength development ofslag activated by alkalis from Portland cement hydra-tion and that of other alkalis, mortars have beenprepared with a range of Portland cement and slagratios (0, 30, 50 and 70o/o slag), while others preparedwith slag activated by alkaline solution with differentconcentration and alkali modulus. The effects ofheatcuring on the strength development of alkali activatedslag (AAS) mortars were also investigated.

2 MATERIALS

2.1 Cementitiotts nruterial.s

Construction grade slag supplied by IndependentCement & Lime Ltd. *'as used for all mortars.Ordinary Portland cement used in this investigationwas general purpose (GP) cement manufactured byCement Australia Ltd. Chemical analysis of thesematerials is given in Table 1.

In general, granulated slag with a chemical com-position which fulfils the criteria on a CaO/SiO2ratio between 0.5 and 2.0 and, an Al2O3/SiO2 ratiobetween 0.1 and 0.6 can be applied (Talling &Brandstetr I 989). Also, to ensure good hydration prop-erties, hydration modulus (HM) which is defined as(CaO+MgO+A1203)/SiO2 should exceed 1.4 (Chang2003). As can be seen from Table 1, the GGBS used inthis experiment has CaO/SiO2 ratio : 1 .2, AlzO:/SiOzratio : 0.4, and HM: 1.83. Therefore it satisfies thecriteria for AAS.r' r,i - - ::1. strength, permeation, and corrosion

505

Table 1 . Composition of cementitious materials

Oxide (%) Cement Slag

Iable 3. Compressive strength of blended cement-slagmortars.

Cementitious (%) Strength (MPa)

Mortar Cement Slag 3d 28d14d7dsio2Al2orFe203CaOMgoK:ONa2OTi02PzosMn2O3SO:s2

CI

19.94.623.97

64.27t.t)0.s70. l50.23

0.062.56

33.,+5

13.460.31

41.7 4s.990.290.160.840.120.402.140.580.01

cso (oPC) 100cs30 70csso 50cs70 30

55

5040l

36292322

0

30

50

70

20

16

1211

464235

31

Table 4. Compressive strength of AAS mortarscuring).

Strength (MPa)Na2O AM(%) (Na2O/SiO2)Mortar 3d 7d 14d

Table 2. Details of the mixes.

Mortar

AAS3-0.75AAS3- 1.00AAS3- 1.25

AAS5-0.75AAS5- 1.00AAS5-1.25

10 13

1s 20t2 17

26 33

35 42)z +o

Cementitious(%)

Cement Slas

Alkaline solution

Na2O AM(% by slag) (Na2O/SiO2)

3

3

3

5

5

5

0.751.001.250.7 51.00t .L)

14

23

20394750cs0 (oPC)

CS3O

CS5O

CSTO

AAS3-0.7sAAS3- 1,00AAS3-1,25AAS5-0.75AAS5-1.00AAS5-1.2s

2.2 Alkaline activators

Grade D sodium . silicate solution (Na2SiO3) of

1.53g/cc density with alkali modulus, AM:2(Na2O= 14.1Yo andSiO2:29.4o7,1 was supplied byPQ Australia. Sodium hydroxide solution (NaOH) wasprepared by dissolving sodium hydroxide peilet withdeionised water.

3 MIX PROPORTIONS AND TESTINGSPECIMENS

A w/b ratio of 0.5 was used to prepare al1 mortars.In the case of AAS mortars, the amount of water inthe mix was the sum of water contained in sodiumsilicate, sodium hydroxide and added water. The sand-cementitious binder ratio was 2.75:1.

Table 2 shows the summary of mortar specimens.Liquid sodium silicate and sodium hydroxide wereblended in different proportions, providing the alka1imodulus in solution (mass ratio of SiO2 to Na2O) rang-in_e trom 0.75 to 1.25. Two levels ofNa2O by slag mass

tn the solution , 3o/o and 50% were investigated. Cr.:::-sponding to the concentration of the alkaline acri', 3- ,r

added in a solution, the amount of water was \,ar.: trl

maintain a constant w/b ratio of 0.5.The mixing were performed using a 5-liters H;:'r

mixer, the mixtures were then poured into 5 cm : r:rimoulds and then vibrated. The specimens were i.: -,.il

24 hours in room temperature and demoulded r:-;n:they were cured at 20oC water for 6 days and rhr:. jf;at room temperature prior to testing. Another i. m

AAS mortar specimens were subjected to 80'C .:rrsrcuring for 24 hours after demoulding and then : -,: risin humidity cabinet at 20"C and 90% relative hu::.,i;n(RH) for further 24 hours and left at room teml3:r:,,n*before testing.

Compressive strength measurements of :-.r:t&flr

100

70

5030

0

305070

100

100

100

100

100

100

-)

l

3

5

5

5

0.151.001.25

0.151.001.25

were performed on an MTS machine in a 1t-.:trol regime with a loading rate of 20MPa mi:-to five cylinders were tested for each data p.r:'specimens were tested at 3, 7, 14, and 28 c;.casting.

- rqry;

- :r:'rot

" -fur'

r.ri1U@t

4 RESULTS AND DISCUSSIONS

4.1. Comparison of strength at normal cti":-.

Strength of blended cement-slag mortars. --rtmortars cured in water at 20'C are shotrn -: -lnulu

and4 respectively. In general, the 28-da1,.s cc:::strength ofAAS mortars of 5%Na2O by sl;: . r.ucomparable with that of Portland cement ::r:1iir

506

: l(i

; ll)

irov0

inSda!!I B 7 tLrvsl

il ?8 di]:

o1'c*

iigure 1. Strength of OPC, blended cement-slag, and AASxortars cured in water at 20'C.

:lended cement-slag mortars as shown in Figure 1. At:lrly age, the 5%NazO AAS mortars were superior..he 3-days compressive strength of 3%Na2O AAS.--ortar is comparable to that of blended cement-slag

-ortar, however the 2S-days strength is significantly.ier. The AAS hardened more rapidly compared

' Portland cement mortar and blended cement-s1ag

- rrtars for similar 28-days strength.On the other hand, the compressive strength of

- ;nded cement-slag mortars up to 28 days is lower-.: OPC mortars, and it is decreased as the level of

',:.acement increased. The hydration of slag needs

. OH)2 from Portland cement hydration, and it. not start until the hydration of PC has taken

' .:e. Therefore concrete containing ground blast,--rce slag usually has longer setting times, lower.' .. strength, but shows higher later strength, denser

,: rstructure and better durability compared with the:.:nd cement concrete (Shi 2004).

- - \ffect of alkali modtilus (AM) and activator: on centration on strength

, . modulus which is defined as ratio of Na2O to

- . n activator has significant influence on strength-. -.S mortars as seen from Figure 1, however the,'::h improvement due to the increase in alkali- -.is was only observed up to AM: I for both- : 5%Na2O AAS mortars.- -::asing the activator concentration (%Na2O by. :ight) has also increased the strength signifi-

. Horvever it is recommended that the maximum

-- : concentration is 5% by slag weight as higher. : . : :n originate efflorescence and brittleness prob-

-. a function of other factors, such as slag.-.ivator nature, and curing temperature. Addi-

. \ ery high activator concentrations are not- :ally recommended (Jimenez et al. 1999).

:-.:r ofheat curing on strength development' | 1.\ mortLrs

- ::ar was found to be very sensitive to heat

Table 5. Compressive strengthofAASmortar(heatcuring).

Strength (MPa)

SampleNa2O AM(%) (NazO/SiOz)

3

3

3

5

5

5

3d 7d r4d 28d

AAS3-0.75AAS3- 1.00AAS3- 1.25AAS5-0.75AAS5- 1.00AAS5- i.25

0.7 5

i.001.25

0.751.001.25

14 15 15)) ,{ )420 21 2344 45 4656 61 6251 55 55

t52423

4763

56

30pi

IEo 20

;15o

7roqEJ

U0

l0 15 20

Age (days)

+ AAS3-0.75 - l- - AAS3-0.75 heat curing

+ AAS3-1.00 -? - AAS3-1.00 heat curing

+ AAS3-1.25 -r - AAS3-1.25 heat curing

Figure 2. Shength development of 3%Nau O AAS monarssubjected to notmal and heat curing.

tL.-

10 15 l0Age (dals)

l5

+ AAS5 0.7-i - + - AA55-0.15 heat curing

+AAS5 1.00 -] --\.\S-5-l.00heatcuring+-AAS5-1.15 -l' .\AS5-l.25hearcuring

Figure 3. Strength development of 5%Na:O AAS mortarssubjecred to norntal and heat curing.

heat cured AAS mortars developed early strengthrapidly compared to normal cured specimens.

For 3%Na2O AAS mortars (Fig. 2), the heat cur-ing increased the early strength. The 3-days strength of

3025

10

tao€5049409ln'i{too.

EroU

030

,---: ----a€#-

ft - r.i can be seen fromTable 5, and Figures 2-3.

507

heat cured 30%Na2O specimens were more than 85% ofits 28-days strength, while the normal cured specimenshad the 3-days strength approximately 60% of the28-days strength. However after 14 days, the 3%Na2Oheat cured specimens did not attained further strengthwhile the normal cured specimens still showed gradualimprovement on strength.

Similar trends were also found at 5%Na2O AASmortars, the heat curing specimens gained approxi-mately 90o/o of the 2S-days strength with in 3 days.The 3-days strength of heat cured specimens evenexceeded the 28-days strength ofnormal cured spec-imens. The 2S-days strength of heat cured specimenswas approximately 8-20o/o higher than that of normalcured specimens, however after 14 days, the 5%Na2Oheat cured specimens did not attained further strengthwhile the normal cured specimens still showed gradualimprovement on strength except for AM : I .25 wherethe strength was constant after 14 days.

5 CONCLUSIONS

The blended cement-slag gain strength more slowlythan Portland cement mortars for the same watercement ratio. On the contrary, the early strengthof AAS mortars was considerably higher than thatof Portland cement mortar for sirrilar 2S-daysstrength.Increasing the alkali modulus (AM) up to 1 incre-ased strength but further increase on AM reducedthe strength.

- Activator concentration has significant influenceon strength, however, it is recommended that5%NazO by slag weight is the limit as the highervalue will be a disadvantage at the later age.Heat treatment considerably accelerates thestrength development of AAS mortar, but at laterages compressive strength of the materials isreduced compared with normal cured specimens.

REFERENCES

Bakharev, T., Sanjayan, J.G. and Cheng, Y-B. 1999. Alkaliactivation of Australian slag cements. Cement and Con-crete Research29(l): ),13 120.

Barnett, S.J., Soutsos, M.N., Millar( S.G. and Bungey, J.H.2006. Strength development ofmortars containing groundgranulated blast-furnace slag: Effect of curing tempera-ture and determination of apparent activation energies.Cement and Concrete Research 36(3): .+34 440.

Chang, J.J. 2003. A study on the setting characteristics oisodium silicate-activated slag pastes. Cement and Con-crete Research 33(7): 1005 101 l.

Jimenez, A.F., Palomo, J.G. and Puertas, F. 1999. Alkal!-activated slag mortars: Mechanical strength behav-iourCement and Concrete Research 29(8): 1 3 I 3-l 32 I .

Gjorv, O.E. 1989. Alkali Activation of a Norwegian Gran:-lated Blast Furnace Slag. In: VM. Malhotra (Ed), F/r.a-.,:silicafume, slag, and natural pozzolans in concrete. Pr,..-Third intern. conJ., Trondheim, Norv,ay I 989 : I 50 I 1 5 I -

Osbome, G. J. 1 999. Durability of Portland blastfurnace s. ":cement concrete . Cement and Concrete Composites 21,'.11-21.

Philleo, R.E. 1989. Slag or other supplementary maren" :In: VM. Malhotra (Ed), Fly ash, silica fume, slag :";natural pozzolans in concrete. Proc. Third intern. . ,'Trondheim, Norway 1989: 1 197-1208.

Shi, C. 2004. Steel Slag Its Production, Processing. Ch-:. .

teristics, and Cementitious Properties. -/ollrnal o./ _1!--, -als in Civil Engineering 16(3):230.

Talling, B., 1989. Effect of Curing Conditions on i. ..: .

Activated Slags. In: VM. Malhotra (Ed), F/r,a-s/:

Jume, slag, and natttral pozzolans in concrete. Pro: l, ,t.,

intern. co4f., Trondheim, Notway 1989:1485 15o,.Talling, B. and Brandstetr, J., 1 989. Pesent State and Fu:-:-r L'

Alkali-Activated Slag Concretes. In: VM. Malhor:. :.iFly ash, silica Junte, slag, and natural pozzolans :- q"

crete. Proc. Third intern. conf., Trondheint, -Nbi-,r:-1519 1545.

508