research article chemical interactions in reinforced...

Research ArticleChemical Interactions in Reinforced ConcreteExposed at a Tropical Marine Environment

Joseacute Manuel Mendoza-Rangel1 Pedro Castro-Borges2 Patricia Quintana-Owen2

Mercedes Balancan-Zapata2 and Jesuacutes Alejandro Cabrera-Madrid2

1Facultad de Ingenierıa Civil Universidad Autonoma de Nuevo Leon (UANL) Avenida Universidad SN Ciudad Universitaria66451 San Nicolas de los Garza NL Mexico2Centro de Investigacion y de Estudios Avanzados del IPN Unidad Merida (CINVESTAV Merida)Carretera Antigua a Progreso Km 6 97310 Merida YUC Mexico

Correspondence should be addressed to Pedro Castro-Borges pcastromdacinvestavmx

Received 17 January 2015 Revised 30 May 2015 Accepted 9 June 2015

Academic Editor Jose L Arias

Copyright copy 2015 Jose Manuel Mendoza-Rangel et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Prediction of concrete structure behavior is complicated by diverse factors including interaction between elements and concretecompounds chlorides diffusion through concrete and compounds formed by corrosion of steel reinforcement These factors wereevaluated in concrete test cylinders exposed to a tropical marine environment since 1993 (during 126 months) Electrochemicalchlorides profile scanning electron microscope and energy-dispersive X-ray spectrophotometry analyses were done and resultscompared This suite of analytical methods accurately characterized reinforced concrete condition and generated data useful indeveloping prediction models of corrosion in concrete structures

1 Introduction

Beginning in the 1980s service life in reinforced concretehas been classified into two stages initiation and propagation[1] However during the last thirty years new more complexmaterials have been incorporated into concrete and environ-mental conditions have changedThese among other factorshave led to development of new systems dividing concreteservice life into stages [2] that more specifically address thephenomena in each stage and adjust them to the changingcircumstances affecting reinforced concrete

Corrosion is more pronounced and common in marineenvironments and very cold places where salt is used fordeicing The main causes of steel corrosion are carbonationand chloride ions [3] Steel reinforcement in concrete is pro-tected against corrosion by a passive film that forms on itssurface in response to the concretersquos high alkalinity (pH= 125to 135) [4] If concrete pH falls below 9 or if chlorides contentexceeds a certain critical value (ie the chlorides threshold)the steelrsquos passive film is lost andwith it any protection against

corrosion Under these conditions corrosion products areformed with an approximate volume five times that of thereinforcing steel producing internal tensions that cause theconcrete covering to fracture and fail

An extensive literature addresses corrosion products onsteel exposed to the environment [5ndash14] The main corro-sion components of these products are iron oxyhydroxides[FeOOH] iron oxides [Fe

2O3] and magnetite [Fe

3O4] On

exposed steel the corrosion process differs from that ofembedded steel reinforcement Scanning electron micro-scope (SEM) studies of the paste-steel interphase in steelreinforcement have identified iron oxide and oxychloride asreaction products [15] A base chloride [3Fe(OH)

2sdotFeCl2] of

iron forms and then decomposes to produce akaganeite [120573-FeOOH] and iron hydroxide [FeOOH] [16] Final corrosionproducts in other studies have included magnetite [Fe

3O4]

and akaganeite [120573-FeOOH] Presence of akaganeite in thecorrosion products is caused by the presence of chloride ionsin the concrete [17]

Hindawi Publishing CorporationJournal of ChemistryVolume 2015 Article ID 864872 5 pageshttpdxdoiorg1011552015864872

2 Journal of Chemistry

Figure 1 Concrete cylinders exposed to a tropical marine environ-ment 100m from the coast at Progreso Yucatan Mexico (21∘181015840N89∘391015840W)

The objective of this paper was to identify the chemicalelements present in the paste-steel interphase and the con-crete paste itself in response to chloride ion ingress throughthe concretersquos pore network the interaction between themtheir effect on structure service life and the correlationbetween the characterization tests and electrochemical testsusing samples exposed to a tropical environment during 126months

2 Experimental Methodology

Samples for this study were taken from simple and rein-forced concrete specimens exposed since 1993 in a tropicalmarine environment at Progreso Yucatan Mexico (21∘181015840N89∘391015840W) all of them were exposed for 126 months in orderto obtain data since the first time of the exposure untilthe detection of reinforcement corrosion [18]The cylindricalspecimens were located 100m from the coast in a verti-cal position (Figure 1) Concrete in the test cylinders wasdesigned to have a resistance of 30MPa and was made with a050 watercement (119908119888) ratio and a one-day set Steel rein-forcement in the test cylinders is 3810158401015840 (95mm) diameterblack steel rebar The superior and inferior surfaces of eachtest cylinder are covered with epoxy to limit chloride actionto the radial surface (Figure 2)

21 Chemical Tests Before the test cylinders were placed inthe marine environment and during 126 months of exposuretests have been done for chlorides and carbonation depthFor chlorides dust samples were taken at seven depths(2 5 10 15 20 25 and 30mm exterior to interior) andchlorides were extracted using the acid extraction techniquefollowing established norms (ASTM C 114 and UNE 217-91)Chlorides concentration was quantified using the selectiveion technique and reference electrodes (Orion models 9417-00 and 9002-00 resp) Carbonation depth was measuredwith the traditional technique of phenolphthalein indicator[19 20] Briefly rounds are cut from the test cylinder dust isimmediately removed from the cut surface with a brush andphenolphthalein is applied to it After application appearanceof a violet color indicates concrete pH higher than 9 and lack

30

mm

90

mm

30

mm

150

mm

75mm

Figure 2 Schematic image of a concrete test cylinder 30MPa com-pression resistance 119908119888 = 050 one-day set

of carbonation while absence of any color means pH is lowerthan 9 and the concrete is carbonated

22 Electrochemical Tests In the reinforced test cylinderssteel reinforcement corrosion potential and rate were evalu-atedwith the polarization resistance technique (Rp) followingnorm ASTM C-876 [21] A potentiostatgalvanostat (PC3ZRA) was used with the steel reinforcement as the workingelectrode and a titanium internal electrode previously cal-ibrated with a calomel-saturated electrode as the referenceelectrode [22]

23 Characterization Tests

231 Corrosion Product Analysis Steel reinforcement corro-sion products were evaluated with SEM (Phillips XL30S) andEDX to identify the elements present on the steel surfaceand in the paste-steel interphase The same analyses werealso done of the concrete paste at different depths to identifywhich elements were present and their concentration Forthese tests rounds were cut from the center of the test cyl-inder and samples cut from these rounds at the depths men-tioned above (Figure 3)

3 Results

The chemical and electrochemical tests of the concrete sam-ples identified the time at which steel reinforcement depas-sivation and corrosion initiation occurred This point alsomarks the end of the initiation stage and the beginning of thepropagation stage

Baseline chlorides content data at the depths mentionedabove were collected before the test cylinders were exposed

Journal of Chemistry 3

20mm

20mm 20mm 75mm

375mm

Figure 3 Test cylinder section profile Samples were taken at dif-ferent depths for SEM and EDX analyses

Table 1 Chloride concentration as a percent () of concrete weightduring the study period

119908119888 Depth (mm) Months0 24 45 78 126

05

2 009 023 018 006 0235 007 023 019 011 02210 009 046 030 022 03715 009 044 057 019 02420 009 046 043 026 02625 008 024 045 021 06230 014 022 020 017 041

This initial pattern was compared to the patterns measured atthe same depths at different exposure times

The free chlorides threshold required to depassivate steelreinforcement and begin its corrosion is reported to bebetween 039 and 116of concreteweight [23] Chloride con-centration per concrete weight in the present data (Table 1)shows that chloride concentration increased over time andfrom the concrete surface towards its interiorMaximumcon-centration was 040 at 126 months and 32mm depth Thisis the depth of the steel surface suggesting that the steel wasdepassivated The chloride concentration profile over time(Figure 4) agrees with those reported in the literature [24]

After 126 months of exposure carbonation had reached20mmdepth Consequently pH had dropped below 9 allow-ing the chlorides to diffuse through the concrete paste Thisis confirmed in the chloride concentration profiles

Electrochemical tests were run to corroborate the chem-ical tests Polarization resistance (Rp) was used to measure

07

06

05

04

03

02

01

00 5 10 15 20 25 30 35

Depth (mm)

Con

cent

ratio

n (

of c

oncr

ete w

eigh

t)

0 months24 months45 months

78 months126 months

Figure 4 Chloride concentration at different depths over time

minus300minus250minus200minus150minus100minus50

050

100150200

310

119

93

150

619

94

281

019

95

110

319

97

240

719

98

061

219

99

190

420

01

010

920

02

140

120

04

280

520

05

101

020

06

220

220

08

060

720

09

Pote

ntia

l (SC

E) (m

V)

Date

0m

onth

s

24

mon

ths

45

mon

ths

78

mon

ths

126

mon

ths

Figure 5 Corrosion potential over time values below minus200mVindicate probable steel corrosion

potentials and calculate corrosion rates Using a coppercop-per sulfate electrode potentials between minus200 and minus400mVare known to indicate possible corrosion of steel (ASTMC-876) The fluctuations in corrosion potential over timeshowed that at 60 and 126 months steel corrosion potentialwas between these values (Figure 5) However they thenrecover and become more positive highlighting the need toconfirm these results with corrosion current measurement in120583Acm2 to determine if corrosion was present on the steelIn this method corrosion is known to exist on steel whencorrosion current density exceeds 01120583Acm2 [25 26]

Data for corrosion rate over time (119894corr) indicated that cur-rent density surpassed 01 120583Acm2 beginning at 126 months(Figure 6) Corrosion had therefore begun previously andcorrosion products are probably present at the interphase Atthis time the test cylinders exhibited plainly visible micro-fractures indicating that corrosion had begun

The EDX analysis showed the amount of elements presentand their proportions (based on peak size) at different depths


0001

001

01

11

311

993

615

199

4

102

819

95

311

199

7

724

199

8

126

199

9

419

200

1

91

2002

114

200

4

528

200

5

101

020

06

222

200

8

76

2009

Date

0m

onth

s

24

mon

ths

45

mon

ths

78

mon

ths

126

mon

ths

i cor

r(120583

Ac

m2)

Figure 6 Value for 119894corr over time values are greater than gt01 120583Acm2 at 126 months

0 100 200 300 400 500 600 700 800 900 1000

COFe

Al

Si

S Cl

Ca

Mn

Fe

Figure 7 EDX analysis showing elements in the interphase andtheir proportions based on peak size

Table 2 Amount of elements ( of weight) as determined by SEM-EDX

Depth(mm) Fe Ca Al Si O Mg S Cl C

0 19 515 17 72 375 0 0 0 02 46 331 30 164 412 08 05 0 05 29 346 25 162 407 20 06 0 010 71 318 48 142 398 20 0 0 015 55 430 29 100 356 07 12 07 020 121 392 70 62 329 09 06 06 025 48 355 28 98 353 08 06 04 9630 27 378 20 105 346 07 07 07 99

(2 5 10 15 20 25 and 30mm) the concrete interphase is at30mm (Figure 7 Table 2)

4 Discussion

The present data indicate that during exposure chloride ionsdiffuse from the exterior inwards through the concretersquos porenetworkThis produces ruptures in the passive layer allowingsteel corrosion to begin Products such as oxychlorides andiron hydroxides form which release iron ions and otherelements such as aluminum and siliconThesemix with otherelements to form compounds which also diffuse through

the concrete paste from the steel reinforcement towards theexterior

It is important to mention that at 20mm depth and 126months of exposure when signs of corrosion were visibletotal chlorides concentration began to decrease while ironand aluminum concentrations at the same depth began toincrease (Figure 4 Table 2) A possible explanation for theseresults is that as the chlorides advance through the concretebulk they mix with other elements such as iron and alu-minum from corrosion products In contrast these diffuseoutwards from the center remaining isolated or mixing littlewith other elements

Silicon levels decreased with depth up to 20mm and thenincreased (Table 2) behavior in good agreement with thecarbonation observed beginning at 20mm in the chemicalanalyses This element forms part of the hydrated calciumsilicates (HCS) in the concrete It is therefore probably dis-solving due to carbonation and then combining with port-landite [Ca(OH)

2] to form calcium carbonate [CaCO

3] since

calcium also decreases at this point (Table 2)Unlike silicon chloride concentration at 126 months and

25mm depth exhibited a maximum peak indeed it was thehighest concentration in a test cylinder (Figure 4 Table 2)At the same depth elements such as iron and aluminumdecreased Silicon concentrations also increased whichagrees with a lack of carbonation at this depth

The data produced to date with this experiment suggeststrong correlations between chemical and electrochemicalphenomena and the behavior of elements and compoundsin the reinforced concrete Further research will be neededto corroborate these findings over longer time periods andin different qualities of concrete The results also confirmthat characterization tests are vital to determining concretedurability and that improvements can be made to an overallservice life prediction model based solely on chloride diffu-sion Stage-based models can help to make predictions moreaccurate

5 Conclusions

Any conclusions drawn from the present study apply largelyto the study conditions and can only be carefully extrapolatedto broader contexts Tools such as SEM and EDX clearlyprovide valuable data for comparing chemical and electro-chemical findings

The chloride ions diffusion from the exterior inwardsthrough the concretersquos pore network produces ruptures in thepassive layer allowing steel corrosion to begin This phe-nomenon can be detected through the joint analyses ofchemical electrochemical and characterization tests This inturn creates greater accuracy in service life predictionmodelsparticularly those divided into various stages

Collecting data from test cylinders exposed for long peri-ods in marine environments helps to establish trustworthydurability parameters that can be compared to real structuresunder service conditions with the additional considerationof factors not included in the present study such as loadconditions


Conflict of Interests

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

Acknowledgments

This work received partial support from the CONACYT(Project no Ciencia Basica 155363) and from the PROMEP(Project no 1035114330) PAICYT (Project no IT520-10)and CONACYT (Project nos Ciencia Basica 57420 andCIAM 54826)

References

[1] K Tuutti ldquoCorrosion of steel in concreterdquo Research Report 4CIB Stockholm Sweden 1982

[2] P Castro-Borges and P Helene ldquoService life of reinforced con-crete structures New approachrdquo ECS Transactions vol 3 no 13pp 9ndash14 2007

[3] G S Duffo W Morris I Raspini and C Saragovi ldquoA study ofsteel rebars embedded in concrete during 65 yearsrdquo CorrosionScience vol 46 no 9 pp 2143ndash2157 2004

[4] C P Page and K W J Treadaway ldquoAspects of the electrochem-istry of steel in concreterdquoNature vol 297 no 5862 pp 109ndash1151982

[5] H Leidheiser Jr and S Music ldquoThe atmospheric corrosion ofiron as studied by Mossbauer spectroscopyrdquo Corrosion Sciencevol 22 no 12 pp 1089ndash1096 1982

[6] H Leidheiser Jr and I Czako-Nagy ldquoA Mossbauer spectro-scopic study of rust formed during simulated atmospheric cor-rosionrdquo Corrosion Science vol 24 no 7 pp 569ndash577 1984

[7] J T Keiser CW Brown and R H Heidersbach ldquoCharacteriza-tion of the passive film formed on weathering steelsrdquo CorrosionScience vol 23 no 3 pp 251ndash259 1983

[8] J B Johnson P Elliott M A Winterbottom and G C WoodldquoShort-term atmospheric corrosion of mild steel at two weatherand pollution monitored sitesrdquo Corrosion Science vol 17 no 8pp 691ndash700 1977

[9] M Stratmann and K Hoffmann ldquoIn situ Moszligbauer spectro-scopic study of reactions within rust layersrdquo Corrosion Sciencevol 29 no 11-12 pp 1329ndash1352 1989

[10] J Avila-Mendoza J M Flores and U C Castillo ldquoEffect ofsuperficial oxides on corrosion of steel reinforcement embed-ded in concreterdquo Corrosion vol 50 no 11 pp 879ndash885 1994

[11] H E Townsend T C Simpson andG L Johnson ldquoStructure ofrust on weathering steel in rural and industrial environmentsrdquoCorrosion vol 50 no 7 pp 546ndash554 1994

[12] A V R Kumar and R Balasubramaniam ldquoCorrosion productanalysis of corrosion resistant ancient indian ironrdquo CorrosionScience vol 40 no 7 pp 1169ndash1178 1998

[13] D C Cook S J Oh R Balasubramanian and M YamashitaldquoThe role of goethite in the formation of the protective corrosionlayer on steelsrdquo Hyperfine Interactions vol 122 no 1-2 pp 59ndash70 1999

[14] T Kamimura T Doi T Tazaki K Kuzushita S Morimoto andS Nasu ldquoInvestigation of rust formed in steels exposed in anindustrial environmentrdquo in Proceedings of the 2nd InternationalConference on Environment Sensitive Cracking and CorrosionDamage pp 190ndash196 Hiroshima Japan 2001

[15] DAKoleva JHuA L A Fraaij K vanBreugel and JHW deWit ldquoMicrostructural analysis of plain and reinforced mortarsunder chloride-induced deteriorationrdquo Cement and ConcreteResearch vol 37 no 4 pp 604ndash617 2007

[16] V S RamachandranConcrete Science chapter 7NoyesWilliamAndrew Norwich UK 2001

[17] B Kounde A Raharinaivo A A Olowe D Rezel P Bauer andJ M R Genin ldquoMossbauer characterization of the corrossionproducts of steels in civil works suspension bridge and rein-forced concreterdquoHyperfine Interactions vol 46 no 1ndash4 pp 421ndash428 1989

[18] P C Borges Difussion and corrosion by chloride ions in rein-forced concrete [PhD thesis] UNAM 1995 (Spanish)

[19] C-F Chang and J-W Chen ldquoThe experimental investigationof concrete carbonation depthrdquo Cement and Concrete Researchvol 36 no 9 pp 1760ndash1767 2006

[20] Y Lo and H M Lee ldquoCuring effects on carbonation of con-crete using a phenolphthalein indicator and Fourier-transforminfrared spectroscopyrdquo Building and Environment vol 37 no 5pp 507ndash514 2002

[21] J A Gonzalez C Andrade C Alonso and S Feliu ldquoChloridethreshold values to depassivate reinforcing bars embedded in astandardized OPC mortarrdquo Cement and Concrete Research vol25 no 2 pp 257ndash264 1995

[22] P Castro A A Sagues E I Moreno L Maldonado and JGenesca ldquoCharacterization of activated titanium solid referenceelectrodes for corrosion testing of steel in concreterdquo Corrosionvol 52 no 8 pp 609ndash617 1996

[23] C Alonso C Andrade M Castellote and P Castro ldquoChloridethreshold values to depassivate reinforcing bars embedded in astandardized OPC mortarrdquo Cement and Concrete Research vol30 no 7 pp 1047ndash1055 2000

[24] P Castro O T De Rincon and E J Pazini ldquoInterpretationof chloride profiles from concrete exposed to tropical marineenvironmentsrdquoCement and Concrete Research vol 31 no 4 pp529ndash537 2001

[25] J A Gonzalez S Algaba and C Andrade ldquoCorrosion ofreinforcing bars in carbonated concreterdquo British Corrosion Jour-nal vol 15 no 3 pp 135ndash139 1980

[26] J A Gonzalez C Andrade C Alonso and S Feliu ldquoCompar-ison of rates of general corrosion and maximum pitting pene-tration on concrete embedded steel reinforcementrdquoCement andConcrete Research vol 25 no 2 pp 257ndash264 1995

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

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International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


Figure 1 Concrete cylinders exposed to a tropical marine environ-ment 100m from the coast at Progreso Yucatan Mexico (21∘181015840N89∘391015840W)

The objective of this paper was to identify the chemicalelements present in the paste-steel interphase and the con-crete paste itself in response to chloride ion ingress throughthe concretersquos pore network the interaction between themtheir effect on structure service life and the correlationbetween the characterization tests and electrochemical testsusing samples exposed to a tropical environment during 126months

2 Experimental Methodology

Samples for this study were taken from simple and rein-forced concrete specimens exposed since 1993 in a tropicalmarine environment at Progreso Yucatan Mexico (21∘181015840N89∘391015840W) all of them were exposed for 126 months in orderto obtain data since the first time of the exposure untilthe detection of reinforcement corrosion [18]The cylindricalspecimens were located 100m from the coast in a verti-cal position (Figure 1) Concrete in the test cylinders wasdesigned to have a resistance of 30MPa and was made with a050 watercement (119908119888) ratio and a one-day set Steel rein-forcement in the test cylinders is 3810158401015840 (95mm) diameterblack steel rebar The superior and inferior surfaces of eachtest cylinder are covered with epoxy to limit chloride actionto the radial surface (Figure 2)

21 Chemical Tests Before the test cylinders were placed inthe marine environment and during 126 months of exposuretests have been done for chlorides and carbonation depthFor chlorides dust samples were taken at seven depths(2 5 10 15 20 25 and 30mm exterior to interior) andchlorides were extracted using the acid extraction techniquefollowing established norms (ASTM C 114 and UNE 217-91)Chlorides concentration was quantified using the selectiveion technique and reference electrodes (Orion models 9417-00 and 9002-00 resp) Carbonation depth was measuredwith the traditional technique of phenolphthalein indicator[19 20] Briefly rounds are cut from the test cylinder dust isimmediately removed from the cut surface with a brush andphenolphthalein is applied to it After application appearanceof a violet color indicates concrete pH higher than 9 and lack

30

mm

90

mm

30

mm

150

mm

75mm

Figure 2 Schematic image of a concrete test cylinder 30MPa com-pression resistance 119908119888 = 050 one-day set

of carbonation while absence of any color means pH is lowerthan 9 and the concrete is carbonated

22 Electrochemical Tests In the reinforced test cylinderssteel reinforcement corrosion potential and rate were evalu-atedwith the polarization resistance technique (Rp) followingnorm ASTM C-876 [21] A potentiostatgalvanostat (PC3ZRA) was used with the steel reinforcement as the workingelectrode and a titanium internal electrode previously cal-ibrated with a calomel-saturated electrode as the referenceelectrode [22]

23 Characterization Tests

231 Corrosion Product Analysis Steel reinforcement corro-sion products were evaluated with SEM (Phillips XL30S) andEDX to identify the elements present on the steel surfaceand in the paste-steel interphase The same analyses werealso done of the concrete paste at different depths to identifywhich elements were present and their concentration Forthese tests rounds were cut from the center of the test cyl-inder and samples cut from these rounds at the depths men-tioned above (Figure 3)

3 Results

The chemical and electrochemical tests of the concrete sam-ples identified the time at which steel reinforcement depas-sivation and corrosion initiation occurred This point alsomarks the end of the initiation stage and the beginning of thepropagation stage

Baseline chlorides content data at the depths mentionedabove were collected before the test cylinders were exposed


20mm

20mm 20mm 75mm

375mm



119908119888 Depth (mm) Months0 24 45 78 126

05

2 009 023 018 006 0235 007 023 019 011 02210 009 046 030 022 03715 009 044 057 019 02420 009 046 043 026 02625 008 024 045 021 06230 014 022 020 017 041





07

06

05

04

03

02

01

00 5 10 15 20 25 30 35

Depth (mm)

Con

cent

ratio

n (

of c

oncr

ete w

eigh

t)


78 months126 months



050

100150200

310

119

93

150

619

94

281

019

95

110

319

97

240

719

98

061

219

99

190

420

01

010

920

02

140

120

04

280

520

05

101

020

06

220

220

08

060

720

09

Pote

ntia

l (SC

E) (m

V)

Date

0m

onth

s

24

mon

ths

45

mon

ths

78

mon

ths

126

mon

ths






0001

001

01

11

311

993

615

199

4

102

819

95

311

199

7

724

199

8

126

199

9

419

200

1

91

2002

114

200

4

528

200

5

101

020

06

222

200

8

76

2009

Date

0m

onth

s

24

mon

ths

45

mon

ths

78

mon

ths

126

mon

ths

i cor

r(120583

Ac

m2)


0 100 200 300 400 500 600 700 800 900 1000

COFe

Al

Si

S Cl

Ca

Mn

Fe




0 19 515 17 72 375 0 0 0 02 46 331 30 164 412 08 05 0 05 29 346 25 162 407 20 06 0 010 71 318 48 142 398 20 0 0 015 55 430 29 100 356 07 12 07 020 121 392 70 62 329 09 06 06 025 48 355 28 98 353 08 06 04 9630 27 378 20 105 346 07 07 07 99


4 Discussion






3] since




5 Conclusions







Acknowledgments


References




































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


20mm

20mm 20mm 75mm

375mm



119908119888 Depth (mm) Months0 24 45 78 126

05

2 009 023 018 006 0235 007 023 019 011 02210 009 046 030 022 03715 009 044 057 019 02420 009 046 043 026 02625 008 024 045 021 06230 014 022 020 017 041





07

06

05

04

03

02

01

00 5 10 15 20 25 30 35

Depth (mm)

Con

cent

ratio

n (

of c

oncr

ete w

eigh

t)


78 months126 months



050

100150200

310

119

93

150

619

94

281

019

95

110

319

97

240

719

98

061

219

99

190

420

01

010

920

02

140

120

04

280

520

05

101

020

06

220

220

08

060

720

09

Pote

ntia

l (SC

E) (m

V)

Date

0m

onth

s

24

mon

ths

45

mon

ths

78

mon

ths

126

mon

ths






0001

001

01

11

311

993

615

199

4

102

819

95

311

199

7

724

199

8

126

199

9

419

200

1

91

2002

114

200

4

528

200

5

101

020

06

222

200

8

76

2009

Date

0m

onth

s

24

mon

ths

45

mon

ths

78

mon

ths

126

mon

ths

i cor

r(120583

Ac

m2)


0 100 200 300 400 500 600 700 800 900 1000

COFe

Al

Si

S Cl

Ca

Mn

Fe




0 19 515 17 72 375 0 0 0 02 46 331 30 164 412 08 05 0 05 29 346 25 162 407 20 06 0 010 71 318 48 142 398 20 0 0 015 55 430 29 100 356 07 12 07 020 121 392 70 62 329 09 06 06 025 48 355 28 98 353 08 06 04 9630 27 378 20 105 346 07 07 07 99


4 Discussion






3] since




5 Conclusions







Acknowledgments


References




































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


0001

001

01

11

311

993

615

199

4

102

819

95

311

199

7

724

199

8

126

199

9

419

200

1

91

2002

114

200

4

528

200

5

101

020

06

222

200

8

76

2009

Date

0m

onth

s

24

mon

ths

45

mon

ths

78

mon

ths

126

mon

ths

i cor

r(120583

Ac

m2)


0 100 200 300 400 500 600 700 800 900 1000

COFe

Al

Si

S Cl

Ca

Mn

Fe




0 19 515 17 72 375 0 0 0 02 46 331 30 164 412 08 05 0 05 29 346 25 162 407 20 06 0 010 71 318 48 142 398 20 0 0 015 55 430 29 100 356 07 12 07 020 121 392 70 62 329 09 06 06 025 48 355 28 98 353 08 06 04 9630 27 378 20 105 346 07 07 07 99


4 Discussion






3] since




5 Conclusions







Acknowledgments


References




































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




Acknowledgments


References




































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

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