Research Article Evaluation of Concrete Durability

Research ArticleEvaluation of Concrete Durability Performance withSodium Silicate Impregnants

Sang-Soon Park1 Yun Yong Kim2 Byung Jae Lee2 and Seung-Jun Kwon3

1 Department of Civil Engineering Sangmyung University 31 Sangmyung-ro Dongnam-gu Cheonan 330-720 Republic of Korea2Department of Civil Engineering Chungnam National University 99 Daehak-ro Yuseong-gu Daejeon 305-764 Republic of Korea3 Department of Civil and Environmental Engineering Hannam University 133 Ojeong-dong Daedeok-guDaejeon 306-791 Republic of Korea

Correspondence should be addressed to Seung-Jun Kwon jjuni98hannamackr

Received 23 April 2014 Revised 24 July 2014 Accepted 26 July 2014 Published 21 August 2014

Academic Editor Tao Zhang

Copyright copy 2014 Sang-Soon Park et alThis is an open access article distributed under the Creative CommonsAttribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

This paper presents an enhanced performance in concrete impregnated with silicate compound Two different types of impregnantmaterials (inorganic and combined type) are applied to concrete samples with different strength grade (21MPa and 34MPa)Through lab-scale test improved performances in impregnated concrete are evaluated regarding porosity strength chloridediffusion coefficient permeability of airwater and absorption Long-term exposure tests including strength chloride penetrationdepth and contents and electrical potential for steel corrosion are performed for different marine conditions While the surface-impregnated concrete shows marginal increase in strength significant improvements of porosity absorption and permeability areevaluatedThe resistance to chloride attack reasonably improved through simply spraying the inorganic silicate in atmospheric-saltspraying condition

1 Introduction

Reinforced concrete (RC) structures usually undergo dete-riorations and the damages due to deteriorations eventuallycause the structural safety problems although they have beenused showing good structural and durability performanceRecently repair techniques using surface-impregnation areproposed for improvement of concrete properties [1ndash4] Theresearch significance of surface-impregnated concrete can beexplained in two viewpoints One is a development of reactiverepair material using silicate compound In 1980ndash90 impreg-nation with sulfate compound was used for improvement ofstrength and elasticity of concrete However the repair tech-nique using additional formation of ettringite due to sulfatecompound had a limited application to concrete structuresbecause another hydration procedure or high temperaturewas required for the impregnation [4] Afterwards liquidorganic or inorganicorganic surface impregnants using sil-icate compound were developed and applied to existing RCstructures as repair techniques [5ndash8] Impregnated silicatecompound such as colloidal silicate and Na-silicate through

capillary suction reacts with the calcium hydroxide-Ca(OH)2

in concrete and produces additional CSH gel [9] Throughthe reaction with SiO

2and Ca(OH)

2 the pore structure

in concrete is modified to be more denser and invisiblemicro cracks can be closed The other is a developmentof repair system using silicate compound and the relatedequipment The organic surface impregnant is mainly usedfor waterproofing and surface protection since it has severaladvantages like low price and easy coating process Howevermost of them are basically constituted of volatile organiccompound and they have the decisive shortcoming of beingair-polluting duringmanufacturing process as well as coatingworks [8] Besides the environmental problem delaminationof impregnation layer easily occurs since organic coatingcannot distribute the evaporation from inner concrete tooutside In addition the material behaviors like shrinkageand thermal expansion in organic coating are significantlydifferent from those in concrete [2] These disharmoniouscharacteristics of surface layer cause cracks delaminationand coming-off from the concrete surface [2 8 10] Thepores and cracks in concrete become such main routes

Hindawi Publishing CorporationAdvances in Materials Science and EngineeringVolume 2014 Article ID 945297 11 pageshttpdxdoiorg1011552014945297

2 Advances in Materials Science and Engineering

Si Si OH

OH

HO

OH

Si

O

OO

Si

SiSi

Si

OH

OHHO Si O SiOSi O Si O( )

OH OH OH OH

Si O Si O Si O Si O( )

OH OH O O

Si

R1

R1R1

R1

R1

R2O OR2

OR2

H2O 3R2OH

3R2OH

3H2O

2H2O OH1

+ +

+

+

+

+

1 2 3

3

4

5

6 7

Figure 1 Chemical chain in inorganic impregnant

for deteriorating agents that durability improvement can beobtained through reducing porosity and permeability [11ndash14]Long-term exposure tests for surface-impregnated concreteare limitedly performed while accelerated deterioration testsin laboratorial scale are widely carried out

This paper presents an enhanced performance of con-crete with impregnation of organic and combined typeFor the purpose two types of surface impregnants whichare inorganic type and combined type are applied to twodifferent concrete levels Properties evaluation tests includingporosity chloride diffusion coefficient compressive strengthpermeation of water and air andmoisture absorption are per-formed Through long-term exposure tests chloride behav-iors and electrical potential for steel corrosion are evaluatedfor the surface-impregnated concrete Quantitative improve-ment of material properties and resistance to chloride attackin concrete with surface impregnation are evaluated anddiscussed in this paper

2 Mechanism of EngineeringProperties Enhancement throughSurface Impregnation

21 Denser Pore Structure with Intrusion of Silicate Com-pound Among the silicate components such as calciumsilicate potassium silicate and colloid silica whichmake porestructure denser through reaction of rehydration sodiumsilicate (Na

2OndashSiO

2) is recently utilized for repair technique

Through capillary suction into concrete this silicate com-pound reacts with calcium hydroxide and eventually formsinsoluble CSH gel (CandashSiO

2) which makes concrete denser

[6ndash8 15] Namely the porosity in concrete is reduced through

the reaction with intruded silicate compound and residualCa(OH)

2 which generally occupies 25ndash30 of amount of

CSH in concrete [16] In the conventional repair system withplate-bonding technique organic adhesive such as epoxyresin is usually used but it cannot guarantee the durabilityperformance under severe condition because of delaminationof protection layer [2 17 18] The material property ofreproduced CSH gel in impregnation layer has the samematerial property as concrete which enables perfect bondwithout delamination of impregnation layer The delami-nation and peeling-off of coating layer frequently occur inorganic coating on concrete surface [8]

The reactions of inorganic and combined type of impreg-nation applied in this study are written in (1) and (2)respectively [6 7]

Na2SiO3+ yH2O + xCa(OH)

2

997888rarr xCa sdot SiO2sdot yH2O + 2NaOH

(1)

R2O sdot SiO

2+ xCaCl

2+ yH2O

997888rarr xCaO sdot SiO2sdot yH2O + ROH

(2)

In Figure 1 chemical compound in inorganic impregnantis shown

22 Reduced Chloride Penetration through Surface-Impreg-nation In hardened concrete chloride ion can be dividedinto free chloride ion affecting steel corrosion directly andbound chloride ion chemically stable without exposure tosevere environmental condition like carbonation [19 20]Formation of bound chloride can be expressed as (3) throughthe reaction with soluble CaCl

2and monosulfate Similar

Advances in Materials Science and Engineering 3

Volume ratioAfter Before

CSH gelPorosity

Chlorideamount

Time

Decreased chloride diffusion due to smaller porosity

Increased binding capacity of chloride ion due to additional CSH

Total chlorideFree chloride

Capillary suction

Impregnation

Recovery of small crack width

Decrease in porosity due to rehydration

Ca(OH)2

depth (3sim4mm)

Figure 2 Durability improvement in surface-impregnated concrete

Table 1 Characteristics of applied surface impregnants

Type Main ingredient Color Viscosity (cp) Surface tension (dynecm) SolventI Inorganic Sodium silicate No color 372 260 AlcoholC Combined inorganicorganic Sodium silicate + polymer Sky blue 413 380 Water

as (3) soluble CaCl2can be changed into insoluble silicate

compound through intrusion of silicate compound as shownin (4)

3CaO sdot Al2O3sdot CaSO

4sdot 12H2O + CaCl

2

997888rarr C3A sdot CaCl

2sdot 10H2O + CaSO

4

(3)

R2O sdot SiO

2+ xCaCl

2+ yH2O


(4)

According to the previous researches [21] chloride ionin pore water can be changed into bound chloride ionthrough absorption to CSH gel and it is related with theamount of CSH gel The resistance to chloride attack can beobtained through both increase in bound chloride ion dueto reproduced CSH and decrease in diffusion of chlorideion due to reduced pore structure in surface-impregnatedlayer If the property of concrete surface is improved it canprovide an effective resistant barrier to chloride attackThesedurability characteristics using improved skin properties areverified by both experiments [5] and analytical solution[22] The enhancing resistance to chloride attack by surface-impregnated concrete can be summarized as Figure 2

3 Experimental Program

31 Materials Used In this paper two surface impregnantsare applied to concrete samples with two different mixproportions One is the inorganic type (I) and the other is thecombined inorganic and organic type (C) The properties ofapplied impregnants are listed inTable 1Themix proportionsof concrete and the physical properties of aggregates are listedin Tables 2 and 3 respectively

32 Experiment Procedures The experiment program in thispaper has two parts one is for evaluation of enhancingproperties after impregnation and the other is for durabilityevaluation under chloride attack for 2 years in exposure test

321 Enhancing of Engineering Properties throughSurface-Impregnation

(1) Curing and Impregnation The tests for enhancementof engineering properties include porosity measurementchloride diffusion coefficient compressive strength perme-ability of airwater and water absorption ratio Concretesamples aremixed based on Table 2 and threefold samples are


Table 2 Mixture proportions of concrete

MPa Slump (cm) wc () Sa W (kgm3) C (kgm3) S (kgm3) G (kgm3)21 15 554 458 166 267 810 97934 15 487 430 185 380 731 994Sa ratio of sand to total aggregate W water C cement S Sand G gravel

Table 3 Physical properties of aggregates

Type 119866max (mm) Density (gcm3) Absorption () Fineness modulusFine aggregate mdash 260 095 264Coarse aggregate 25 265 085 680

Table 4 Specimens and curing procedures

Test Specimens (mm) Curing and impregnationPorosity 50 times 50 times 50 (cubic) (1) Mixing based on Table 2

(2) Curing in air for 1 day(3) Curing in water for 4 weeks(4) Drying in air for 2 weeks(5) Spraying impregnant(6) Curing in air for 2 weeks

Chloride diffusion coefficient 100 times 50 (cylinder)Compressive strength 100 times 200 (cylinder)Permeability of water and air 200 times 200 times 100 (rectangular)Absorption 100 times 100 times 100 (cubic)

manufactured for each test Each sample is demolded after 1day and cured in submerged condition (20∘C of temperature)for 4 weeks After curing for 4 weeks they are exposed to airfor 2 weeks and then surface impregnation was performedthrough spraying The test items size of sample and curingprocedures are summarized in Table 4

(2) Tests for Impregnated Concrete For the control concrete(21MPa and 34MPa) and impregnated concrete (I andC type) porosity is measured through mercury intrusionporosimetry (MIP) The porosity in impregnated concreteis reduced through additionally reproduced CSH so thatdurability performance can be improved They are measuredbased on the related guideline [23] For design of durabilitychloride diffusion coefficient is essential parameter In thistest accelerated test in nonstationary condition is performedbased on the previous research [24] Chloride diffusioncoefficient can be obtained as follows

119863cpd =

119877119879119871

119911119865119880

sdot

119909119889minus 120572radic119909

119889

119905

120572 = 2radic119877119879119871

119911119865119880

sdot erfminus1 [1 minus

2119862119889

1198620

]

(5)

where 119863cpd is diffusion coefficient in nonsteady state condi-tion from rapid chloride penetration test (m2sec) 119877 is uni-versal gas constant (8314 JmolsdotK) 119879 is absolute temperature(K)119871 is thickness of specimen (m) 119911 is ionic valence (=10)119865is Faraday constant (=96500 JV mol) 119880 is applied potential(V) 119909

119889is the penetration depth of chloride ion (m) 119905 is

test duration time (sec) 1198620is chloride concentration in the

upstream solution (molL) 119862119889is chloride concentration at

the chloride penetration front (molL) and erfminus1 is the inverseof the error function

Compressive strength is considered as basic parameterfor property evaluation so that compressive strength test is

also performed referring KS F 2405 [25] Permeabilities ofwater and air have important roles of durability performancesince they are directly related to moisture transport Becauseconcrete in partially saturated condition always has moisturegradient evaporation occurs on the surface When theinorganic material without moisture evaporation to outersurface is coated it causes delamination and peeling-off ofcoating material [8] The permeability of water and air canbe calculated through (6) and (7) respectively [6 7]

119862119862119875

=

119902

119875119871(6)

119870 = 4[

119881119888(119889119875119868119889119905)2

119860 (1198752

119886minus 1198752

119868)

]

120583119875119886

120576

int

119905

1199050

[1 minus (

119875119868

119875119886

)

2

]119889119905 (7)

where 119862119862119875

is permeability of water (m2sec) 119902 is velocity(msec) 119875 is pressure (BAR) 119871 is depth of gasket (15mm)119870 is permeability of air (m2) 120576 is porosity in concrete (1m3)119860 is area of chamber 120583 is dynamic viscosity of air (Nsm2) 119875

119868

and 119875119886are pressure in chamber and air respectively (Nm2)

and 119881119888is volume of chamber (m3)

In order to obtain absorption ratios for the different con-crete samples the impregnated specimens kept in submergedcondition for 72 hours after curing shown in Table 4 based onKS F 2459 [26]The absorption ratio can be obtained through

119860 =

1198822minus 1198821

1198821

times 100 (8)

where 119860 is absorption ratio () and 1198821(g) and 119882

2(g)

are weight of specimens before and after the submergedcondition respectively

322 Enhancing Durability through Surface-Impregnation

(1) Compressive Strength Test method and mix design forconcrete are same as those for compressive strength test


(a) Exposure to tidal condition (b) Spraying 01N AgNO3 (c) Test for HCP

Figure 3 Photos for long-term chloride exposure test

described in Section 321 The concrete specimens are curedfor 2 weeks in submerged condition and impregnation is per-formed after 2 weeks of exposure to air After impregnationthey are exposed to tidal zone of sea water The compressivestrength is evaluated at the age of 28 days 90 days 360 daysand 720 daysThree concrete samples are prepared for averagevalue in the each measuring time

(2) Chloride Penetration Depth The cylindrical samples(100mm times 200mm) with same curing and impregnationprocedures are prepared and exposed to chloride conditionsThe samples with 21MPa are exposed to atmospheric (salt-sprayed) tidal and sea water submerged conditions Thosewith 34MPa are exposed to only tidal condition For themeasurement of chloride penetration depth splitting test isperformed and AgNO

3solution (01N) as an indicator is

sprayed on the split section based on the previous research[27] For measurement of chloride penetration depth thecolored depths are measured 10 times with 10mm intervaland the averages are used It is reported that color in splitlayer changes when free chloride concentration reaches 015(cement weight) through 01N AgNO

3indicator For the

sake of convenience colorimetric method of 01N AgNO2is

adopted in this paperThe optimum indicator and proceduresvary with test methods and chloride concentration Thereactive indicators with various colorimetric methods arewell summarized in the reference [28]

(3) Electrical Potential for Steel Corrosion For evaluation ofsteel corrosion electrical potentials (Half Cell Potential) aremeasured for RC samples (50 times 50 times 400mm) based onASTM C 876-80 [29] The conditions of curing and exposurefor this test are same as those for chloride penetration depthSteel reinforcement of 10mm diameter is embedded in RCspecimen which has 20mm cover depth The exposed rebarfrom concrete surface is coated with epoxy for preventingcorrosion In Figure 3 photos for long-term chloride expo-sure tests are shown

(4) Chloride Content Evaluation (Acid-Soluble) In order toevaluate the chloride content exposed to chloride attackcylindrical samples (100 times 200mm) are exposed to tidal andsubmerged conditions For 1-dimensional intrusion side andbottom are coated with epoxy and only top surface is directlyexposed to sea water Based on AASHTO T 260 standard

solution of AgNO3is used for determining the chloride

content After grinding concrete cover with 10mm depth theparticles are tested with adding HNO

3

4 Results and Discussion

41 Improved Properties of Surface-Impregnated ConcretePorosity in the case of 21MPa decreases to 628sim744 com-pared with control results Results in the case of 34Mpa showreduction to 454sim917 and they are reduced significantlysince they have more Ca(OH)

2which can react with silicate

compound Pores in concrete are much related with diffusionmechanism so that reduced chloride diffusion coefficient canbe obtained through impregnation Chloride diffusion coef-ficient decreases to 85 (21MPa) and 716sim748 (34MPa)When we assume 100mmof cover depth and critical chloridecontent of 12 kgm3 service life is evaluated to increasefrom 378 years to 505 year through simply spraying I typeimpregnant to 34MPa concrete based on Fickrsquos 2nd Law[30] For compressive strength it is measured that results inboth impregnated concrete samples slightly increase becausematerial properties are improved only within the impreg-nated depth (below 10mm) No significant development instrength is measured in the test The strength gaining ratiosare evaluated to be 1124ndash1212 (for 21MPa concrete) and1141ndash1161 (for 34MPa concrete) Permeability of waterairis the unique characteristics of porous media like concreteIt is strongly related with transport of external agents so thatit can be used as durability index [31] In water permeabilitytest reduction ratios to control samples are measured tobe 454ndash500 in surface-impregnated concrete with 21MPaand 256ndash273 in that with 34MPa In air permeability testreduction ratios are also measured to be 867 in surface-impregnated concrete with 21MPa and 850ndash900 in thatwith 34MPa respectively Similarly as the results of com-pressive strength there is no significant difference from theimpregnant types While the surface-impregnated concreteshows significantly reduced water permeability the effectof impregnation on air permeability seems to be marginalAs previously explained delamination between concrete andsurface coating easily occur in organic impregnated concretesince coating on surface cannot permit evaporation to outersurface [2 6ndash8 10] The improved property with lower-ing water permeability but maintaining air permeability is


Table 5 Summary of modified properties tests

Test items Concrete-21MPa ( to control of 21MPa) Concrete-34Mpa ( to control of 34MPa)Control C type I type Control C type I type

Porosity () 258 (1000) 192 (744) 162 (628) 202 (1000) 185 (917) 92 (454)Chloride diffusion coefficient (m2sec) 261 (1000) 223 (854) 223 (854) 155 (1000) 111 (716) 116 (748)Compressive strength (MPa) 250 (1000) 281 (1124) 303 (1212) 298 (1000) 340 (1141) 346 (1161)Water permeability (10minus14msec) 1707 (1000) 854 (500) 776 (454) 1538 (1000) 420 (273) 394 (256)Air permeability (10minus16m2) 23 (1000) 20 (869) 20 (869) 20 (1000) 18 (900) 17 (850)Absorption () 27 (1000) 07 (257) 05 (169) 21 (1000) 05 (259) 04 (185)

0

10

20

30

40

Test

resu

lts fo

r pro

pert

ies

ControlC typeI type

Poro

sity

()

Com

pres

sive

stren

gth

(MPa

)

Chlo

ride d

iffus

ion

coeffi

cien

t(10minus13

m2s

)

Wat

er

perm

eabi

lity

(10minus13

ms

)

Air

perm

eabi

lity

(10minus17

m2)

Abso

rptio

nra

tiotimes10

()

(a) Results for concrete of 21MPa

0

10

20

30

40

Test

resu

lts fo

r pro

pert

ies

ControlC typeI type

Poro

sity

()

Com

pres

sive

stren

gth

(MPa

)

Chlo

ride d

iffus

ion

coeffi

cien

t(10minus13

m2s

)

Wat

er

perm

eabi

lity

(10minus13

ms

)A

ir pe

rmea

bilit

y(10minus17

m2)

Abso

rptio

nra

tiotimes10

()

(b) Results for concrete of 34MPa

Figure 4 Results for modified properties test

a notable engineering advantage and this can prevent thedelamination of impregnated layer The surface-impregnatedconcrete has hydrophobic characteristics so that it can reducethe intrusion of water Reduction ratios in absorption test aremeasured to be 169ndash257 in surface-impregnated concretewith 21MPa and 185ndash259 in that with 34MPa For overalltest results the concrete with inorganic coating (I type) showsslightly better enhanced performances both in concrete of21MPa and 34MPa The results for improved properties aresummarized in Table 5 and Figure 4 Figures 4(a) and 4(b)show the results of impregnated concrete of 21MPa and34MPa respectively

The effect of surface impregnation on engineering proper-ties is evaluated to be remarkable in reducing porosity waterpermeability and absorption ratio among the others

42 Durability Evaluation for Surface-Impregnated Concrete

421 Compressive Strength in Long-Term Exposure to Chlo-ride Attack As shown in Figure 5 compressive strength inimpregnated concrete shows increase with exposure periodbut no clear strength gaining The impregnated depth isusually 5-6mm when it is sprayed In the results in Table 5

strength increasing ratios are 1124ndash1212 however theresults in this section are different from those in Table 5because of their different curing conditions and periodIt is recommended to take a conservative repair strategythrough disregarding an increase in strength Slight increasein compressive strength is measured in surface-impregnatedconcrete with 21MPa while it is goes down to 926ndash945in 34MPa concrete Considering the harsh environmentalcondition like tidal zone where physical and chemical attacksact simultaneously the difference ofmeasured strength seemsto be small

422 Chloride Penetration Depth in Long-Term Exposure toChloride Attack Themeasurements of the chloride penetra-tion depth with different exposure conditions are shown inFigure 6 As described in Section 322 samples with 21MPaare located in 3 different conditions like atmospheric tidaland submerged condition Those with 34MPa are locatedonly in tidal condition

In durability design the chloride penetration depth withcritical chloride amount (ie 12 kgm3) should be smallerthan the cover depth within the intended service period since


0

10

20

30

40

50

0 200 400 600 800

Com

pres

sive s

treng

th (M

Pa)

Exposed period (days)

Control (21MPa)C type (21MPa)I type (21MPa)


Figure 5 Change in compressive strength in surface-impregnated concrete under long-term exposure condition

0

10

20

30

40

0 120 240 360 480 600 720

Pene

trat

ion

dept

h (m

m)

Period (days)


(a) 21MPa atmospheric condition

0

10

20

30

40Pe

netr

atio

n de

pth

(mm

)

0 120 240 360Period (days)


(b) 21MPa tidal condition

0

10

20

30

40

0 120 240 360

Pene

trat

ion

dept

h (m

m)

Period (days)


(c) 21MPa submerged condition

0

10

20

30

40

Pene

trat

ion

dept

h (m

m)

0 120 240 360Period (days)


(d) 34MPa tidal condition

Figure 6 Chloride penetration depth in surface-impregnated concrete


Table 6 Decrease ratio of chloride penetration depth

Period (days) Condition Control C type I typeRatio of chloride penetration depth (21MPa )

360 Tidal 1000 943 800360 Submerged 1000 867 833720 Salt-sprayed 1000 750 583

Ratio of chloride penetration depth (34MPa )360 Tidal 1000 1000 81

00 120 240 360 480 600 720

Elec

tric

pot

entia

ls (m

V)

Period (days)

ControlC type (21MPa)I type (21MPa)

minus200

minus400

minus600

minus800

(a) Potential (21MPa submerged condition)

0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800

(b) Potential (21MPa tidal condition)

0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800

(c) Potential (34MPa tidal condition)

0 100 200 300 400 500 600 700 800Period(days)


0

Elec

tric

pot

entia

ls (m

V)

minus100

minus200

minus300

minus400

(d) Potential (21MPa atmospheric condition)

Figure 7 Result of measured potential in surface-impregnated concrete

chloride ion is one of the most critical deteriorating agent forits rapid propagation and its direct effect on steel corrosion[1 12 27 29] As shown in Figure 6 chloride penetrationdepth is reduced in both I and C type impregnated concretethrough enhancement of surface impregnationThe concretesamples with inorganic impregnation show better resistanceto chloride penetration and this trend is clear with the longer

exposure period The resistance to chloride attack is closelyrelated to impregnation depth of silicate The impregnationdepth increases with activated capillary suction which iscaused by lower viscosity and surface tension of impregnanttype [5ndash7] The ratio of chloride penetration depth is listedin Table 6 Unlike strength evaluation it shows reasonableresistance to chloride penetration


0

1

2

3

4

5

6

0 001 002 003 004 005Concrete depth (m)

Tota

l chl

orid

e con

tent

(kg

m3)

Control

C type (21MPa)I type (21MPa)

(a) Chloride profile (21MPa submerged condition)

0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control


(b) Chloride profile (21MPa tidal condition)

0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control


(c) Chloride profile (34MPa tidal condition)

0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control


(d) Chloride profile (21MPa atmospheric condition)

Figure 8 Total chloride profile in concrete withwithout impregnation after 2 years

423 Electric Potential for Steel Corrosion (Copper-CopperSulfate Half Cell CSE) It is reported that steel corrosioneasily occurs at the location where lower electrical potentialis measured since possibility of corrosion is governed byelectrical potential and resistivity around steel location [2932] The results of electronic potential indicate an improvedresistance to steel corrosion as shown in Figure 7

Potential in surface-impregnated concrete with 21MPa inFigure (b) is evaluated to be similar as that in nonsurface-impregnated concrete with 34MPa in Figure (c) It shows thatconcrete with low strength can obtain reasonable resistanceto chloride attack like concrete with high strength by simplespraying of surface impregnation In every condition con-crete with I type impregnation has better resistance to steelcorrosion than that with C type impregnation Previouslydescribed lower viscosity and surface tension of I type aremore effective to impregnation According to the perviousresearches [31 32] probability of steel corrosion is higher

than 90 in the concrete area under minus350mV of HCPWhile the electric potential in control decreases to the levelof critical value (minus350mV) after 18 years the others withimpregnation show higher potential than minus350mV after2 years as shown in Figure 7(d) The decrease ratios ofmeasured electrical potential after 2 years are listed in Table 7The effect of impregnation is shown to be most effective inatmospheric condition since the intruded silicate compoundis not distilled and impeded by water intrusion and leachingout

424 Profiles of Total Chloride Contents In Figure 8 chlorideprofiles are shown for concrete in tidal and salt-sprayedconditions Chloride profiles in the results show impregnatedconcrete have improved resistance to chloride penetrationSimilarly as durability test results I type impregnationwith lower viscosity and surface tension shows better resis-tance than C type impregnation With simplified regression


0 05 1 15 2 25 3 35 4

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (34MPa)

I type (34MPa)

C type (34MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)

Apparent diffusion coefficient (10minus12 m2s)

conditionAtmospheric

Tidal condition

Tidal condition

conditionSubmerged

Figure 9 Derived apparent diffusion coefficient and surface chloride contents

Table 7 Decrease ratio of electrical potential after 2 years

Period (days) Condition Control C type I typeDecrease ratio of potential (21MPa )

720Tidal 1000 936 886Submerged 1000 918 824Salt-sprayed 1000 785 692

Decrease ratio of potential (34MPa )720 Tidal 1000 916 848

analysis apparent diffusion coefficients are obtained andplotted in Figure 9 The effects of reduction ratio regardingapparent diffusion coefficient are 425ndash686 for I typeimpregnation and 532ndash729 for C type impregnation

5 Concluding Remarks

The conclusions on evaluation of concrete durability perfor-mance with sodium silicate impregnants are as follows

(1) The surface-impregnated concrete shows marginalincrease in compressive strength For conservativerepair design it is reasonable not to consider thestrength gaining in surface-impregnated concreteThe enhancement effects of surface impregnation areremarkably observed in reducing water permeabilityabsorption and porosity

(2) I type (inorganic) impregnated concrete has slightlybetter resistance to chloride penetration than theC type (combined inorganicorganic) impregnatedconcrete due to lower viscosity and surface tensionwhich cause deeper impregnation depth After 360days it is measured that the chloride penetrationdepths in impregnated concrete of 21MPa decrease to800sim943 of those in control concrete under tidal

condition 833sim867 under submerged conditionand 583sim750under salt-sprayed condition respec-tively

(3) After impregnation the results of the electrical poten-tial in concrete with 21MPa and 34MPa decrease to692sim918 and 848sim916 of those in control con-crete respectively The surface-impregnated concretewith 21MPa shows similar durability performanceas nonsurface-impregnated concrete with 34MPa inelectrical potentials for corrosion

(4) Through analysis on chloride profiles apparent dif-fusion coefficients are reduced to 425ndash686 forI type impregnation and 532ndash729 for C typeimpregnation The effect is smaller than reductionof permeability and porosity however reasonableresistance to chloride attack can be obtained by simplyspraying sodium silicate compound

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper


Acknowledgment

This work was supported by the National Research Founda-tion of Korea (NRF) funded by the Ministry of Education(NRF-2011-0025378)

References

[1] CEB Durable Concrete StructuresmdashCEB Design Guide ThomasTelford 1992

[2] P H Emmons Concrete Repair and Maintenance IllustratedRS Means Company 1994

[3] L C Bank Composites for Construction Structural Design withFRP Material John Wiley amp Sons 2006

[4] Y Ohama ldquoRecent progress in concrete-polymer compositesrdquoAdvanced Cement Based Materials vol 5 no 2 pp 31ndash40 1997

[5] E I Yang M Y Kim B C Lho and J H Kim ldquoEvaluationon resistance of chloride attack and freezing and thawing ofconcrete with surface penetration sealerrdquo Journal of the KoreaConcrete Institute vol 18 no 1 pp 65ndash72 2006

[6] S J Kwon S S Park S M Lee and J H Kim ldquoA study ondurability improvement for concrete structures using surfaceimpregnantrdquo Journal of Korea Structure Maintenance Institutevol 11 no 4 pp 79ndash88 2007

[7] S J Kwon S S Park S M Lee and J W Kim ldquoSelection ofconcrete surface impregnant through durability testsrdquo Journalof Korea Structure Maintenance Institute vol 11 no 6 pp 77ndash86 2007

[8] H Y Moon D G Shin and D S Choi ldquoEvaluation ofthe durability of mortar and concrete applied with inorganiccoating material and surface treatment systemrdquo Constructionand Building Materials vol 21 no 2 pp 362ndash369 2007

[9] I Narai-Sabo Inorganic Crystallochemistry ACSC PublicationsBudapest Hungary 1969

[10] KICTTEP ldquoTechnique for water-tightness improvement ofconcrete surface using water tightness agent and air pressureequipmentrdquo Report for New Technology 334 2002

[11] S J Kwon Durability analysis in cracked concrete exposed cou-pled chloride attack and carbonation [PhD thesis] Departmentof Civil Engineering Yonsei University Seoul Republic ofKorea 2006

[12] H W Song S W Pack C H Lee and S J Kwon ldquoService lifeprediction of concrete structures under marine environmentconsidering coupled deteriorationrdquo Restoration of Buildings andMonuments vol 12 no 4 pp 265ndash284 2006

[13] H Song and S Kwon ldquoPermeability characteristics of carbon-ated concrete considering capillary pore structurerdquoCement andConcrete Research vol 37 no 6 pp 909ndash915 2007

[14] H W Song S J Kwon K J Byun and C K Park ldquoPredictingcarbonation in early-aged cracked concreterdquo Cement and Con-crete Research vol 36 no 5 pp 979ndash989 2006

[15] V Kasselouri N Kouloumbi and T Thomopoulos ldquoPerfor-mance of silica fume-calcium hydroxide mixture as a repairmaterialrdquo Cement and Concrete Composites vol 23 no 1 pp103ndash110 2001

[16] T Ishida and K Maekawa ldquoModeling of PH profile in porewater based on mass transport and chemical equilibriumtheoryrdquo Concrete Library International JSCE vol 37 no 3 pp131ndash146 2003

[17] F Tomosawa and T Nakatsuji ldquoEvaluation of ACM reinforce-ment durability by exposure testrdquo in Proceedings of the Interna-tional 3rd Symposium on Non-Metallic (FRP) Reinforcement forConcrete Structures vol 2 pp 139ndash146 1997

[18] A Nanni T Boothby K M Cetim B A Shaw and C BakisldquoEnvironmental degradation of repaired concrete structurerdquo inProceedings of the 3rd International Symposium on Non-Metallic(FRP) Reinforcement for Concrete Structures vol 2 pp 155ndash1621997

[19] A Neville ldquoChloride attack of reinforced concrete anoverviewrdquo Materials and Structures vol 28 no 2 pp 63ndash701995

[20] K Tuutti ldquoCorrosion of steel in concreterdquo CBI Report 4-82 Swedish Cement and Concrete Research Institute(CBI)Stockholm Sweden 1982

[21] T Luping and L Nilsson ldquoChloride binding capacity andbinding isotherms of OPC pastes and mortarsrdquo Cement andConcrete Research vol 23 no 2 pp 247ndash253 1993

[22] C Andrade JMDıez andC Alonso ldquoMathematicalmodelingof a concrete surface ldquoskin effectrdquo on diffusion in chloridecontaminated mediardquo Advanced Cement Based Materials vol6 no 2 pp 39ndash44 1997

[23] Micromeritics ldquoAutoPore IV 9505 Operatorrsquos Manualrdquo 2005[24] T Luping and L Nilsson ldquoRapid determination of the chloride

diffusivity in concrete by applying an electrical fieldrdquo ACIMaterials Journal vol 89 no 1 pp 40ndash53 1992

[25] Korea Standard ldquoMethod of test for compressive strength ofconcreterdquo KS F 2405 2005

[26] Korea Standard ldquoTesting method for density water contentabsorption and compressive strength of cellular concreterdquo KSF 2459 2002

[27] N Otsuki S Nagataki and K Nakashita ldquoEvaluation of theAgNO

3solution spray method for measurement of chloride

penetration into hardened cementitiousmatrixmaterialsrdquoCon-struction and Building Materials vol 7 no 4 pp 195ndash201 1993

[28] F He C Shi Q Yuan C Chen and K Zheng ldquoAgNO3-based

colorimetric methods for measurement of chloride penetrationin concreterdquo Construction and Building Materials vol 26 no 1pp 1ndash8 2012

[29] American Society for Testing and Materials ldquoHalf-cell poten-tials of reinforcing steel in concretemdashdesignationrdquo Book ofASTM Standards C 876-80 Section 4 American Society forTesting and Materials Philadelphia Pa USA 1980

[30] M D A Thomas and E C Bentz ldquoComputer program forpredicting the service life and life-cycle costs of reinforcedconcrete exposed to chloridesrdquo Life365 Manual SFA 9984-952002

[31] J Glanville and A Neville Prediction of Concrete DurabilityProceedings of STATS 21st Anniversary Conference Eamp FNSponLondon UK 1st edition 1995

[32] J P Broomfield Corrosion of Steel in Concrete UnderstandingInvestigation and Repair 2nd edition 1997

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


Si Si OH

OH

HO

OH

Si

O

OO

Si

SiSi

Si

OH

OHHO Si O SiOSi O Si O( )

OH OH OH OH

Si O Si O Si O Si O( )

OH OH O O

Si

R1

R1R1

R1

R1

R2O OR2

OR2

H2O 3R2OH

3R2OH

3H2O

2H2O OH1

+ +

+

+

+

+

1 2 3

3

4

5

6 7

Figure 1 Chemical chain in inorganic impregnant

for deteriorating agents that durability improvement can beobtained through reducing porosity and permeability [11ndash14]Long-term exposure tests for surface-impregnated concreteare limitedly performed while accelerated deterioration testsin laboratorial scale are widely carried out

This paper presents an enhanced performance of con-crete with impregnation of organic and combined typeFor the purpose two types of surface impregnants whichare inorganic type and combined type are applied to twodifferent concrete levels Properties evaluation tests includingporosity chloride diffusion coefficient compressive strengthpermeation of water and air andmoisture absorption are per-formed Through long-term exposure tests chloride behav-iors and electrical potential for steel corrosion are evaluatedfor the surface-impregnated concrete Quantitative improve-ment of material properties and resistance to chloride attackin concrete with surface impregnation are evaluated anddiscussed in this paper

2 Mechanism of EngineeringProperties Enhancement throughSurface Impregnation

21 Denser Pore Structure with Intrusion of Silicate Com-pound Among the silicate components such as calciumsilicate potassium silicate and colloid silica whichmake porestructure denser through reaction of rehydration sodiumsilicate (Na

2OndashSiO

2) is recently utilized for repair technique

Through capillary suction into concrete this silicate com-pound reacts with calcium hydroxide and eventually formsinsoluble CSH gel (CandashSiO

2) which makes concrete denser

[6ndash8 15] Namely the porosity in concrete is reduced through

the reaction with intruded silicate compound and residualCa(OH)

2 which generally occupies 25ndash30 of amount of

CSH in concrete [16] In the conventional repair system withplate-bonding technique organic adhesive such as epoxyresin is usually used but it cannot guarantee the durabilityperformance under severe condition because of delaminationof protection layer [2 17 18] The material property ofreproduced CSH gel in impregnation layer has the samematerial property as concrete which enables perfect bondwithout delamination of impregnation layer The delami-nation and peeling-off of coating layer frequently occur inorganic coating on concrete surface [8]

The reactions of inorganic and combined type of impreg-nation applied in this study are written in (1) and (2)respectively [6 7]

Na2SiO3+ yH2O + xCa(OH)

2

997888rarr xCa sdot SiO2sdot yH2O + 2NaOH

(1)

R2O sdot SiO

2+ xCaCl

2+ yH2O


(2)

In Figure 1 chemical compound in inorganic impregnantis shown

22 Reduced Chloride Penetration through Surface-Impreg-nation In hardened concrete chloride ion can be dividedinto free chloride ion affecting steel corrosion directly andbound chloride ion chemically stable without exposure tosevere environmental condition like carbonation [19 20]Formation of bound chloride can be expressed as (3) throughthe reaction with soluble CaCl

2and monosulfate Similar



CSH gelPorosity

Chlorideamount

Time




Capillary suction

Impregnation



Ca(OH)2

depth (3sim4mm)







4sdot 12H2O + CaCl

2


2sdot 10H2O + CaSO

4

(3)

R2O sdot SiO

2+ xCaCl

2+ yH2O


(4)


















119863cpd =

119877119879119871

119911119865119880

sdot

119909119889minus 120572radic119909

119889

119905

120572 = 2radic119877119879119871

119911119865119880


2119862119889

1198620

]

(5)








119862119862119875

=

119902

119875119871(6)

119870 = 4[

119881119888(119889119875119868119889119905)2

119860 (1198752

119886minus 1198752

119868)

]

120583119875119886

120576

int

119905

1199050

[1 minus (

119875119868

119875119886

)

2

]119889119905 (7)

where 119862119862119875


119868




119860 =

1198822minus 1198821

1198821

times 100 (8)


2(g)











3indicator For the







3









0

10

20

30

40

Test

resu

lts fo

r pro

pert

ies

ControlC typeI type

Poro

sity

()

Com

pres

sive

stren

gth

(MPa

)

Chlo

ride d

iffus

ion

coeffi

cien

t(10minus13

m2s

)

Wat

er

perm

eabi

lity

(10minus13

ms

)

Air

perm

eabi

lity

(10minus17

m2)

Abso

rptio

nra

tiotimes10

()


0

10

20

30

40

Test

resu

lts fo

r pro

pert

ies

ControlC typeI type

Poro

sity

()

Com

pres

sive

stren

gth

(MPa

)

Chlo

ride d

iffus

ion

coeffi

cien

t(10minus13

m2s

)

Wat

er

perm

eabi

lity

(10minus13

ms

)A

ir pe

rmea

bilit

y(10minus17

m2)

Abso

rptio

nra

tiotimes10

()











0

10

20

30

40

50

0 200 400 600 800

Com

pres

sive s

treng

th (M

Pa)





0

10

20

30

40

0 120 240 360 480 600 720

Pene

trat

ion

dept

h (m

m)

Period (days)



0

10

20

30

40Pe

netr

atio

n de

pth

(mm

)

0 120 240 360Period (days)



0

10

20

30

40

0 120 240 360

Pene

trat

ion

dept

h (m

m)

Period (days)



0

10

20

30

40

Pene

trat

ion

dept

h (m

m)

0 120 240 360Period (days)









00 120 240 360 480 600 720

Elec

tric

pot

entia

ls (m

V)

Period (days)


minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 100 200 300 400 500 600 700 800Period(days)


0

Elec

tric

pot

entia

ls (m

V)

minus100

minus200

minus300

minus400






0

1

2

3

4

5

6

0 001 002 003 004 005Concrete depth (m)

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control









0 05 1 15 2 25 3 35 4

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (34MPa)

I type (34MPa)

C type (34MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)



Tidal condition

Tidal condition

conditionSubmerged

















Acknowledgment


References











































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





CSH gelPorosity

Chlorideamount

Time




Capillary suction

Impregnation



Ca(OH)2

depth (3sim4mm)







4sdot 12H2O + CaCl

2


2sdot 10H2O + CaSO

4

(3)

R2O sdot SiO

2+ xCaCl

2+ yH2O


(4)


















119863cpd =

119877119879119871

119911119865119880

sdot

119909119889minus 120572radic119909

119889

119905

120572 = 2radic119877119879119871

119911119865119880


2119862119889

1198620

]

(5)








119862119862119875

=

119902

119875119871(6)

119870 = 4[

119881119888(119889119875119868119889119905)2

119860 (1198752

119886minus 1198752

119868)

]

120583119875119886

120576

int

119905

1199050

[1 minus (

119875119868

119875119886

)

2

]119889119905 (7)

where 119862119862119875


119868




119860 =

1198822minus 1198821

1198821

times 100 (8)


2(g)











3indicator For the







3









0

10

20

30

40

Test

resu

lts fo

r pro

pert

ies

ControlC typeI type

Poro

sity

()

Com

pres

sive

stren

gth

(MPa

)

Chlo

ride d

iffus

ion

coeffi

cien

t(10minus13

m2s

)

Wat

er

perm

eabi

lity

(10minus13

ms

)

Air

perm

eabi

lity

(10minus17

m2)

Abso

rptio

nra

tiotimes10

()


0

10

20

30

40

Test

resu

lts fo

r pro

pert

ies

ControlC typeI type

Poro

sity

()

Com

pres

sive

stren

gth

(MPa

)

Chlo

ride d

iffus

ion

coeffi

cien

t(10minus13

m2s

)

Wat

er

perm

eabi

lity

(10minus13

ms

)A

ir pe

rmea

bilit

y(10minus17

m2)

Abso

rptio

nra

tiotimes10

()











0

10

20

30

40

50

0 200 400 600 800

Com

pres

sive s

treng

th (M

Pa)





0

10

20

30

40

0 120 240 360 480 600 720

Pene

trat

ion

dept

h (m

m)

Period (days)



0

10

20

30

40Pe

netr

atio

n de

pth

(mm

)

0 120 240 360Period (days)



0

10

20

30

40

0 120 240 360

Pene

trat

ion

dept

h (m

m)

Period (days)



0

10

20

30

40

Pene

trat

ion

dept

h (m

m)

0 120 240 360Period (days)









00 120 240 360 480 600 720

Elec

tric

pot

entia

ls (m

V)

Period (days)


minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 100 200 300 400 500 600 700 800Period(days)


0

Elec

tric

pot

entia

ls (m

V)

minus100

minus200

minus300

minus400






0

1

2

3

4

5

6

0 001 002 003 004 005Concrete depth (m)

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control









0 05 1 15 2 25 3 35 4

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (34MPa)

I type (34MPa)

C type (34MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)



Tidal condition

Tidal condition

conditionSubmerged

















Acknowledgment


References











































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials














119863cpd =

119877119879119871

119911119865119880

sdot

119909119889minus 120572radic119909

119889

119905

120572 = 2radic119877119879119871

119911119865119880


2119862119889

1198620

]

(5)








119862119862119875

=

119902

119875119871(6)

119870 = 4[

119881119888(119889119875119868119889119905)2

119860 (1198752

119886minus 1198752

119868)

]

120583119875119886

120576

int

119905

1199050

[1 minus (

119875119868

119875119886

)

2

]119889119905 (7)

where 119862119862119875


119868




119860 =

1198822minus 1198821

1198821

times 100 (8)


2(g)











3indicator For the







3









0

10

20

30

40

Test

resu

lts fo

r pro

pert

ies

ControlC typeI type

Poro

sity

()

Com

pres

sive

stren

gth

(MPa

)

Chlo

ride d

iffus

ion

coeffi

cien

t(10minus13

m2s

)

Wat

er

perm

eabi

lity

(10minus13

ms

)

Air

perm

eabi

lity

(10minus17

m2)

Abso

rptio

nra

tiotimes10

()


0

10

20

30

40

Test

resu

lts fo

r pro

pert

ies

ControlC typeI type

Poro

sity

()

Com

pres

sive

stren

gth

(MPa

)

Chlo

ride d

iffus

ion

coeffi

cien

t(10minus13

m2s

)

Wat

er

perm

eabi

lity

(10minus13

ms

)A

ir pe

rmea

bilit

y(10minus17

m2)

Abso

rptio

nra

tiotimes10

()











0

10

20

30

40

50

0 200 400 600 800

Com

pres

sive s

treng

th (M

Pa)





0

10

20

30

40

0 120 240 360 480 600 720

Pene

trat

ion

dept

h (m

m)

Period (days)



0

10

20

30

40Pe

netr

atio

n de

pth

(mm

)

0 120 240 360Period (days)



0

10

20

30

40

0 120 240 360

Pene

trat

ion

dept

h (m

m)

Period (days)



0

10

20

30

40

Pene

trat

ion

dept

h (m

m)

0 120 240 360Period (days)









00 120 240 360 480 600 720

Elec

tric

pot

entia

ls (m

V)

Period (days)


minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 100 200 300 400 500 600 700 800Period(days)


0

Elec

tric

pot

entia

ls (m

V)

minus100

minus200

minus300

minus400






0

1

2

3

4

5

6

0 001 002 003 004 005Concrete depth (m)

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control









0 05 1 15 2 25 3 35 4

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (34MPa)

I type (34MPa)

C type (34MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)



Tidal condition

Tidal condition

conditionSubmerged

















Acknowledgment


References











































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










3indicator For the







3









0

10

20

30

40

Test

resu

lts fo

r pro

pert

ies

ControlC typeI type

Poro

sity

()

Com

pres

sive

stren

gth

(MPa

)

Chlo

ride d

iffus

ion

coeffi

cien

t(10minus13

m2s

)

Wat

er

perm

eabi

lity

(10minus13

ms

)

Air

perm

eabi

lity

(10minus17

m2)

Abso

rptio

nra

tiotimes10

()


0

10

20

30

40

Test

resu

lts fo

r pro

pert

ies

ControlC typeI type

Poro

sity

()

Com

pres

sive

stren

gth

(MPa

)

Chlo

ride d

iffus

ion

coeffi

cien

t(10minus13

m2s

)

Wat

er

perm

eabi

lity

(10minus13

ms

)A

ir pe

rmea

bilit

y(10minus17

m2)

Abso

rptio

nra

tiotimes10

()











0

10

20

30

40

50

0 200 400 600 800

Com

pres

sive s

treng

th (M

Pa)





0

10

20

30

40

0 120 240 360 480 600 720

Pene

trat

ion

dept

h (m

m)

Period (days)



0

10

20

30

40Pe

netr

atio

n de

pth

(mm

)

0 120 240 360Period (days)



0

10

20

30

40

0 120 240 360

Pene

trat

ion

dept

h (m

m)

Period (days)



0

10

20

30

40

Pene

trat

ion

dept

h (m

m)

0 120 240 360Period (days)









00 120 240 360 480 600 720

Elec

tric

pot

entia

ls (m

V)

Period (days)


minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 100 200 300 400 500 600 700 800Period(days)


0

Elec

tric

pot

entia

ls (m

V)

minus100

minus200

minus300

minus400






0

1

2

3

4

5

6

0 001 002 003 004 005Concrete depth (m)

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control









0 05 1 15 2 25 3 35 4

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (34MPa)

I type (34MPa)

C type (34MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)



Tidal condition

Tidal condition

conditionSubmerged

















Acknowledgment


References











































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials







0

10

20

30

40

Test

resu

lts fo

r pro

pert

ies

ControlC typeI type

Poro

sity

()

Com

pres

sive

stren

gth

(MPa

)

Chlo

ride d

iffus

ion

coeffi

cien

t(10minus13

m2s

)

Wat

er

perm

eabi

lity

(10minus13

ms

)

Air

perm

eabi

lity

(10minus17

m2)

Abso

rptio

nra

tiotimes10

()


0

10

20

30

40

Test

resu

lts fo

r pro

pert

ies

ControlC typeI type

Poro

sity

()

Com

pres

sive

stren

gth

(MPa

)

Chlo

ride d

iffus

ion

coeffi

cien

t(10minus13

m2s

)

Wat

er

perm

eabi

lity

(10minus13

ms

)A

ir pe

rmea

bilit

y(10minus17

m2)

Abso

rptio

nra

tiotimes10

()











0

10

20

30

40

50

0 200 400 600 800

Com

pres

sive s

treng

th (M

Pa)





0

10

20

30

40

0 120 240 360 480 600 720

Pene

trat

ion

dept

h (m

m)

Period (days)



0

10

20

30

40Pe

netr

atio

n de

pth

(mm

)

0 120 240 360Period (days)



0

10

20

30

40

0 120 240 360

Pene

trat

ion

dept

h (m

m)

Period (days)



0

10

20

30

40

Pene

trat

ion

dept

h (m

m)

0 120 240 360Period (days)









00 120 240 360 480 600 720

Elec

tric

pot

entia

ls (m

V)

Period (days)


minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 100 200 300 400 500 600 700 800Period(days)


0

Elec

tric

pot

entia

ls (m

V)

minus100

minus200

minus300

minus400






0

1

2

3

4

5

6

0 001 002 003 004 005Concrete depth (m)

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control









0 05 1 15 2 25 3 35 4

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (34MPa)

I type (34MPa)

C type (34MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)



Tidal condition

Tidal condition

conditionSubmerged

















Acknowledgment


References











































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0

10

20

30

40

50

0 200 400 600 800

Com

pres

sive s

treng

th (M

Pa)





0

10

20

30

40

0 120 240 360 480 600 720

Pene

trat

ion

dept

h (m

m)

Period (days)



0

10

20

30

40Pe

netr

atio

n de

pth

(mm

)

0 120 240 360Period (days)



0

10

20

30

40

0 120 240 360

Pene

trat

ion

dept

h (m

m)

Period (days)



0

10

20

30

40

Pene

trat

ion

dept

h (m

m)

0 120 240 360Period (days)









00 120 240 360 480 600 720

Elec

tric

pot

entia

ls (m

V)

Period (days)


minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 100 200 300 400 500 600 700 800Period(days)


0

Elec

tric

pot

entia

ls (m

V)

minus100

minus200

minus300

minus400






0

1

2

3

4

5

6

0 001 002 003 004 005Concrete depth (m)

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control









0 05 1 15 2 25 3 35 4

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (34MPa)

I type (34MPa)

C type (34MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)



Tidal condition

Tidal condition

conditionSubmerged

















Acknowledgment


References











































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials








00 120 240 360 480 600 720

Elec

tric

pot

entia

ls (m

V)

Period (days)


minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 120 240 360 480 600 720Period (days)


0

Elec

tric

pot

entia

ls (m

V)

minus200

minus400

minus600

minus800


0 100 200 300 400 500 600 700 800Period(days)


0

Elec

tric

pot

entia

ls (m

V)

minus100

minus200

minus300

minus400






0

1

2

3

4

5

6

0 001 002 003 004 005Concrete depth (m)

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control









0 05 1 15 2 25 3 35 4

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (34MPa)

I type (34MPa)

C type (34MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)



Tidal condition

Tidal condition

conditionSubmerged

















Acknowledgment


References











































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0

1

2

3

4

5

6

0 001 002 003 004 005Concrete depth (m)

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control



0 001 002 003 004 005Concrete depth (m)

0

1

2

3

4

Tota

l chl

orid

e con

tent

(kg

m3)

Control









0 05 1 15 2 25 3 35 4

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (34MPa)

I type (34MPa)

C type (34MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)



Tidal condition

Tidal condition

conditionSubmerged

















Acknowledgment


References











































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0 05 1 15 2 25 3 35 4

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)

Control (34MPa)

I type (34MPa)

C type (34MPa)

Control (21MPa)

I type (21MPa)

C type (21MPa)



Tidal condition

Tidal condition

conditionSubmerged

















Acknowledgment


References











































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




Acknowledgment


References











































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



Documents

Research Article Evaluation of Concrete Durability