prevention of reinforcement corrosion in concrete by sodium … · 2019. 7. 30. · prevention of...

Research ArticlePrevention of Reinforcement Corrosion in Concrete by SodiumLauryl Sulphate Electrochemical and Gravimetric Investigations

Binsi M Paulson1 Thomas K Joby 1 Vinod P Raphael 2 and K S Shaju 2

1Research Division Dept of Chemistry St Thomasrsquo College (Autonomous) Thrissur Kerala 680001 India2Dept of Chemistry Government Engineering College Thrissur Kerala 680009 India

Correspondence should be addressed toThomas K Joby drjobythomaskgmailcom

Received 24 August 2018 Revised 27 October 2018 Accepted 13 November 2018 Published 2 December 2018

Academic Editor Ramazan Solmaz

Copyright copy 2018 BinsiM Paulson et alThis is an open access article distributed under theCreativeCommonsAttribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Prolonged corrosion inhibition response of sodium lauryl sulphate (SLS) on steel reinforcement in contaminated concrete wasinvestigated by gravimetric method and electrochemical techniques such as potentiodynamic polarization and electrochemicalimpedance spectroscopy Using half cell potential measurements probability of steel reinforcement corrosion was monitored fora period of 480 days FT-IR spectroscopic analysis of the corroded products deposited on the steel reinforcement revealed themechanism of corrosion inhibition Modification in the surface morphology of steel specimens in the concrete was examined byoptical microscopy During the period of investigation (480 days) SLS showed appreciable corrosion inhibition efficiency on thesteel reinforcement in concrete

1 Introduction

Reinforced concrete structures are developed to ensure thestrength and existence throughout their lifetime But thedeterioration and collapse of reinforced concrete structureare a major issue in construction field [1ndash3] CO

2from

the air and chloride ions from the sea atmosphere enterinto the concrete and make the concrete interstitial solutionmore aggressive than before [4ndash8] Depassivation of the steelreinforcement occurs locally in the presence of chlorideions leading to pitting corrosion [9ndash12] Passivation of steelreinforcement takes place due to the alkaline compoundspresent in the concrete The cost of replacing deterioratedconcrete structures may affect the GDP (Gross DomesticProduct) of a country To find out an effective and economicmethod to combat the steel reinforcement corrosion inconcrete has been attracted by the researchers and engineersfor the last two decades

Addition of the corrosion inhibitors to the concretemixture is the most practical way tominimize steel reinforce-ment corrosion in contaminated concrete [13ndash16] In idealsituations corrosion inhibitors will not affect the propertiesof the concrete Some of the previous researchers havebeen established that inhibitor molecules generally affect the

kinetics of electrochemical process of corrosion of steel [17ndash19] The mechanism of corrosion inhibition by the addedcompounds may include lowering of the rate of diffusionof chloride ion enhancing the threshold value of chlorideion and lowering the rate of anodic and cathodic process ofcorrosion [20ndash22] Corrosion inhibitors can be added to thefresh concrete as an admixture during concrete casting stepor can be applied on the concrete surface

Commercially available corrosion inhibitors may containeither organic or inorganic compounds like sodium nitritesodium monofluorophosphate aminoethanols and so forth[23ndash27] Nowadays use of nitrites is not recommendeddue to its toxicity The efficacies of organic inhibitors aresometimes questionable at elevated chloride concentrationsResearchers scientists and engineers are always in searchof potent economic and environmental-friendly admixturesto combat steel reinforcement corrosion in concrete Somerecently invented green inhibitors like silver nanoparticledoped palm oil leaf extracts [28] and naturally obtainedWelan gum and Neem gum [29] have predominant concretecorrosion inhibition efficiency

Present investigation was conducted to check the cor-rosion preventing capacity of SLS on steel reinforcement

HindawiInternational Journal of CorrosionVolume 2018 Article ID 9471694 10 pageshttpsdoiorg10115520189471694

2 International Journal of Corrosion

SS mesh

ElectrochemicalWorkstation

Rebar

Wet sponge

SCE

Figure 1 Three-electrode circuitry for electrochemical studies

in contaminated concrete [30 31] Preliminary examina-tions were done by measuring the electrode potentials ofsteel reinforcements (against SCE) dipped in concrete poresolution contaminated with 35 NaCl containing variousconcentrations of SLS After this examination we decidedto investigate the corrosion response of steel reinforcementin concrete specimen containing 25 of SLS by weight ofcement

2 Experimental

21 Materials Sodium lauryl sulphate and sodium chloride(gt999 ) were procured from Merck Millipore Portlandcement (Indiana Cements Grade 53) used for making con-crete specimens was purchased from the market

22 Preparation of Concrete Test Specimens Concrete blockscontaining steel reinforcement used for the experiment weremade of Portland cement coarse aggregate fine aggregate(sand) and water Each rectangular block having dimensionof 200x80x80mm was prepared by mixing water and cementin the ratio 05The ratio between cement fine aggregate andcoarse aggregate was 1153 which will exactly mimic M-20grade concrete SLS was added to the concrete mixture by25 wt of cement and two test specimens were casted Inthis work we designate the concrete specimen without SLSas SAMPLE 1 and with SLS as SAMPLE 2 The approximatecomposition of steel rod was estimated by EDAXmethod 01 P 062 Mn 0021 Si 004 S and rest Fe Steel rebarswere cut (22 cm) and immersed in 2M HCl for 10 minutesfor removing the rust washed with distilled water degreasedwith acetone dried weighed and used as the reinforcementin concrete After a period of 24 h the test specimens wereremoved from themould and cured for 30 days for the properhydration and setting of the cement

23 Treatment of Test Specimens After the curing periodfive sides of the test specimens were coated with epoxyresin and one open reservoir (100x40x20mm) was built onthe remaining side with polypropylene and silicon adhesive

25mL 35NaCl was added to the reservoir of the specimensand kept for 2 days This will ensure the complete diffusionof NaCl throughout the specimen This process was repeatedthree times during 30-60 days

24 Electrochemical Investigations

(i) Potentiodynamic Polarization Studies Figure 1 shows theschematic diagram of the test specimen and the experi-mental setup for electrochemical studies Three-electrodecell assembly consisting of steel reinforcement present inconcrete as working electrode concrete specimen coveredwith a stainless steel mesh as counter electrode and saturatedcalomel electrode (SCE) as reference electrode were used forthe electrochemical studies [32] For good electrical contacta wet sponge was used on the concrete surface between SCEand concrete surface

After curing and treatment of test specimens with NaClpolarization studies were performed three times during aperiod of 480 days in 160 daysrsquo interval Steel reinforcement inthe concrete was scanned for a potential range of +250 to -250mV having a scan rate of 1mVs Tafel curves were analyzedto get the slopes which are extrapolated to get the corrosioncurrent densities The corrosion inhibition efficiency of SLSwas determined using the following equation

120578pol =119868corr minus 119868

1015840

corr119868corr

X100 (1)

where Icorr and I1015840corr are corrosion current densities of steelreinforcement in test specimens in the absence and presenceof SLS respectively Experiments were repeated with theduplicate concrete block and the average values were taken

(ii) Electrochemical Impedance Spectroscopic (EIS) Studies EISexperiments were carried out at constant potential in thefrequency range of 1 KHz to 100 mHz with excitation signalof 10mV amplitude Analysis of the Nyquist curves using theequivalent circuit gave the charge transfer resistance (Rct)

International Journal of Corrosion 3

Table 1 Tafel data of steel reinforcement in concrete in the presence and absence of SLS for different periods

Time System Icorr ba -bc -Ecorr 120578pol (day) (120583Acm2) (mVdec) (mVdec) (mV)160 SAMPLE 1 161 496 159 651

SAMPLE 2 18 430 232 573 89320 SAMPLE 1 139 489 156 662

SAMPLE 2 41 469 229 520 71480 SAMPLE 1 107 373 215 551

SAMPLE 2 21 341 230 561 80

Using Rct values corrosion inhibition efficacy of SLS wasdetermined using the following equation

120578EIS =R1015840ct minus Rct

RctX100 (2)

where R1015840ct and Rct are the charge transfer resistance ofworking electrode with and without SLS respectively Polar-ization and EIS analyses were done using Ivium CompactStatelectrochemical work station (IviumSoft)

(iii) Half Cell Potential Measurements For understanding thecorrosion response of steel reinforcement in concrete halfcell potential measurements were carried out using saturatedcalomel electrode (SCE) and high impedance voltmeter (HPE2378A) In this electrochemical cell steel reinforcementand SCE were acted as anode and cathode respectively Thepotential of the steel rebar was obtained by deducting the cellpotential from the standard electrode potential of saturatedcalomel electrode Sixteen readings were taken with a regularinterval of 1 reading per month during 480 days

25 Gravimetric Method Before casting the concrete blockseach steel rebar was pickled with 2M HCl for 10 minuteswashed with water degreased with acetone dried andweighed The surface areas of all reinforcements were thesame (105cm2) After 480 days concrete blocks were brokenand the steel reinforcementswere taken outside pickled using2M HCl for 15 minutes to remove the adhered rust washedwith water dried and weighed From the weight loss of thesteel specimens approximate corrosion inhibition efficiencyof SLS was calculated by the following equation

120578 = 1199080 minus 1199081199080

times 100 (3)

where w0and w are the weight loss of steel rebars of SAMPLE

1 and SAMPLE 2

26 Spectroscopic Studies Fourier Transform Infrared (FT-IR) spectroscopic study of corroded product on the steelreinforcement was conducted using KBr pellet method Thespectrum was recorded in the range of 400-4000cmminus1 usingShimadzu IR Affinity-1 model FT-IR spectrophotometer

27 Microscopic Surface Analysis After 480 days of elec-trochemical investigation the steel specimens were taken

outside from the concrete and analyzed using a high-resolution optical microscope (Leica Stereo Microscope NoS8ACO) This study mainly aims to understand the surfacemodifications that occurred for steel specimen during theperiod of investigation

3 Results and Discussions

31 Potentiodynamic Polarization Studies The inhibition effi-cacy of SLS and site of corrosion inhibition on steel rein-forcement in the contaminated concrete wasmonitored usingpotentiodynamic polarization studies Analysis of polariza-tion curve gave Tafel slopes current densities and percentageof inhibition efficiency which are given in Table 1 Fromthe data it is understandable that the steel reinforcementin the concrete containing SLS was less corroded than rein-forcement in the SAMPLE 1 During 480 days three sets ofmeasurements were taken in 160 daysrsquo interval It was noticedthat SLS exhibited 89 corrosion inhibition efficiency on160th day of study On 320th and 480th days of investigationinhibition efficiency changed to 71 and 80 respectivelyFrom these results it can be assured that SLS can act asan efficient admixture which resists the steel reinforcementcorrosion in the contaminated concrete structures for a longtime SLS mainly acted on cathodic sites of corrosion up to23 rd period of investigation since the cathodic slopes of theTafel lines altered appreciably (Figure 2) But the corrosioninhibition response of SLS was changed into mixed type(affecting both anodic and cathodic sites) towards the end ofstudy

The gradation in the inhibition efficiency of SLS can beexplained with the help of following hypothesis The entireperiod of investigation can be divided into three stages firststage (0-160 days) second stage (161-320 days) and third stage(321-480 days) In the first stage SLS molecules adjacent tothe steel rebar make coordinate bonds with ferrous ions andprevent chloride ions and water molecules diffusing towardsthe steel surface considerably Thus during this period SLSprotects well the corrosion of reinforcement Towards theend of second stage (320 days) it was observed that the rateof corrosion slightly increased Since the rate of diffusion ofchloride ion is greater than that of SLS higher percentage ofchloride ions can be expected near the steel surface than thatof first stage The porous nature of the hydrated ferric oxidehelps to enter water molecules chloride and oxygen moretowards the steel surface Thus SLS showed less corrosion


Sample 1

160 days320 days480 days

minus03minus05 minus04minus06 minus02minus08 minus07

Potential (V)

minus25

minus20

minus15

minus10

minus05

00

05

10

15

log

curr

ent d

ensit

y(Ac

m

)

(a)

Sample 2


minus07 minus06 minus05 minus04 minus03 minus02minus08

Potential(V)

minus35

minus30

minus25

minus20

minus15

minus10

minus05

00

05

10

log

curr

ent d

ensit

y(Ac

m

)

(b)

Figure 2 Tafel curves of steel reinforcement in concrete (a) in the absence and (b) presence of SLS for 160 320 and 480 days

Table 2 EIS parameters of steel reinforcement in concrete in the presence and absence of inhibitor for different periods

Time Sample W Rs Cdl Rct 120578(day) (Ohmsqrt(Hz) (Ωcm2) (120583Fcmminus2) (Ωcm2)160 SAMPLE 1 274 785 110 119

SAMPLE 2 502 975 109 931 872320 SAMPLE 1 352 157 885 147

SAMPLE 2 927 459 42 665 78480 SAMPLE 1 323 223 273 243

SAMPLE 2 158 574 096 173 86

protection efficacy at this stage In the third stage (480 days)the rate of corrosion was seemed to decrease again (but not asthat much of first stage) During the end of this stage it can bebelieved thatmore andmore SLSmoleculesmigrated towardsthe steel surface from the bulk and make more coordinatebonds with ferrous ions and protect steel surface This led tohigher corrosion protection efficiency of SLS than in secondstage

32 EIS Measurements The corrosion response of steel rein-forcement in concrete in the presence and absence of SLS wasmonitored using electrochemical impedance spectroscopyand the corresponding Nyquist plots are represented inFigure 3 The corrosion behaviour of steel reinforcement wassignificantly differed in the presence and absence of inhibitorThe equivalent circuit fitted for EIS measurements (Figure 4)consists of solution resistance (Rs) which is connected inseries to double layer capacitance (C

1) and this combination

is connected in parallel to a series combination of Warburgresistance (W) and charge transfer resistance (Rct) [33 34]The EIS parameters of the test specimens are given in Table 2Impedance data show that addition of SLS leads to the

decrease in double-layer capacitance and increase of chargetransfer resistance This is due to the adsorption of SLSmolecules on the steel rebar SLS exhibited 872 corrosioninhibition efficiency on 160th day of investigation Inhibitionefficiencies changed to 78 and 86 respectively on the 320th

and 480th days of study

33 Half Cell Potential Measurements The probability ofcorrosion of steel reinforcement in concrete was visualizedwith the help of half cell potential measurements It wasestablished by the previous researchers that tendency ofcorrosion increases as the potential of the steel reinforcementchanges to more anodic side Half cell potentials (Vs SCE)of steel reinforcements in concrete blocks during 480 dayswere measured at a time interval of 30 days and are givenin Table 3 The half cell potential values are compared withthe help of a line graph and are represented in Figure 5Data show that the steel reinforcement in concrete block(SAMPLE 1) exhibited high anodic potential values which isa clear reflection of high corrosion rate in the contaminatedconcrete Half cell potentials of steel specimen in SAMPLE 2were less negative (more cathodic) than SAMPLE 1 during the


2

3

1

2 3

1

1 160 days

Sample 1

Sample 2

2 320 days3 480 days

1 160 days2 320 days3 480 days

00

05

10

15

20

25

30

minusZ

(o

hm cＧ

2)

15 20 25 3010Z

(ohm cＧ2)

0

5

10

15

20

25

30

35

40

minusZ

(o

hm cＧ

2)

60 180 100 120 140 160 180 200 22040Z

(ohm cＧ2)

(a)

2 3

3

1

21

Sample 1

Sample 2



12 14 16 18 20 22 24 26 28 301010log(frequency)Hz

0

200

400

600

800

1000

10lo

gZo

hm

0

200

400

600

800

1000

10lo

gZo

hm

60 180 100 120 140 160 180 2004010log(frequency)Hz

(b)

Figure 3 Nyquist plots and Bode plots of steel reinforcement in concrete (a) in the absence and (b) presence of SLS for 160 320 and 480days

Rs

W

Cdl

Rct

Figure 4 Equivalent circuit fitted for EIS measurements of steelreinforcement in contaminated concrete

period of investigation These results show that SLS is actingas a good corrosion inhibitor on steel reinforcement throughthe period of investigation

34 Gravimetric Analysis Gravimetric analysis of steel rein-forcement in SAMPLE 1 and SAMPLE 2 was done forexamining the percentage of weight loss and the approximate

corrosion inhibition efficacy of SLS After the period ofinvestigation steel specimens were taken outside from theconcrete block pickled with HCl dried and weighed Steelreinforcements of SAMPLE 1 and SAMPLE 2 displayedweight losses of 24 and 36 respectively Thus the inter-vention of SLS on the steel rebar in concrete contaminatedwith NaCl was well established Approximate value of corro-sion inhibition efficiency of SLS determined by gravimetricstudies was 86

35 FT-IR Analysis IR spectral studies of the corroded prod-uct gave an idea about the nature of interaction of SLS on steelreinforcement Surface deposits were removed and subjectedto spectral analysis Various compounds such as ferrous andferric hydroxides hydrated ferric oxide and ferrous chloridemay be deposited on the steel reinforcement A broad signalobserved at 3375 cmminus1 in the spectrum of corroded productof SAMPLE 1 was due to ndashOH stretching frequency of ferroushydroxide or hydrated ferric oxide (or both) [35] In the IRspectrum of corroded product of SAMPLE 2 it was noticed


Table3Halfcellp

otentia

l(mV)o

fsteelreinforcem

entinconcretein

thep

resencea

ndabsenceo

fSLS

for4

80days

Day

3060

90120

150

180

210

240

270

300

330

360

390

420

450

480

SAMPL

E1

-607

-588

-580

-555

-560

-554

-567

-578

-611

-592

-625

-628

-589

-602

-597

-600

SAMPL

E2

-416

-463

-420

-423

-514

-457

-497

-473

-440

-416

-499

-516

-535

-399

-397

-389


Sample 1Sample 2

100 200 300 400 5000Days

minus650

minus600

minus550

minus500

minus450

minus400

Hal

f cel

l pot

entia

l

Figure 5 Variation of half cell potentials of steel reinforcement in contaminated concrete in the absence (SAMPLE 1) and presence (SAMPLE2) of SLS during 480 days

Corrosion product on steel rebar (sample 1)

3000 2000 1000 04000

3375

4411471

638

1619

868

1350

-1Wavenumber (cＧ )

minus50

0

50

100

150

200

250

300

350

400

T

rans

mitt

ance

(a)

3349

2895

28022347

16331420

1104955

789

2922

2821

16521466

1244

1067984

826

Corrosion product on steel (Sample 2)

4000 25003500 50020003000 10001500Wavenumber cＧ-1

minus10

0

10

20

30

40

50

60

70

80

90

100

110

T

rans

mitt

ance

SLS

2376

(b)

Figure 6 IR spectrum of oxide film deposited on the steel reinforcement in (a) SAMPLE 1 and (b) SAMPLE 2 and spectrum of SLS

that the peak due to ndashOH frequency shifted to 3349 cmminus1This may be due to the interaction of SLS with the ferrous orferric hydroxide The IR spectrum of sodium lauryl sulphatecontains peaks at 2922 and 2821 cmminus1 which can assignedto the stretching frequencies of various C-H This peak wasvisible at 2895 cmminus1 in the spectrum of surface productof SAMPLE 2 steel specimen In the IR spectrum of SLStwo IR regions corresponding to symmetric and asymmetricstretching frequency of sulphate group appeared at 826-1240cmminus1 and 1240-1466cmminus1 respectively These peaks wereshifted to 789-1104cmminus1 and 1104-1420cmminus1 in the spectrumof corroded product of SAMPLE 2 This is clear indication ofthe interaction of SLS through the sulphate end A weak peakcorresponding to the C-C stretching frequency of carbon

skeleton displayed at 964cmminus1 in the IR spectrum of SLSwas shifted to 955cmminus1 Two intense peaks at 2821cmminus1and 2922cmminus1 corresponding to symmetric and asymmetricstretching frequencies of CH

2groups of SLS also shifted to

2802cmminus1 and 2895cmminus1 in the FT-IR spectrum of surfacedeposits of steel in SAMLE 2 Figure 6 represents thespectrum of SLS and the IR spectrum of oxide film depositedon the steel reinforcement in SAMPLE 1and SAMPLE 2

36 Microscopic Surface Analysis Micrographs of bare steelrebar and steel reinforcements of SAMPLE 1 and SAMPLE 2after the investigation period are given in Figure 7 Surface ofsteel rebar in SAMPLE 1 contained large amount of hydratedferric oxide It is evident that enhanced corrosion of the


(a) (b)

(c)

Figure 7 Optical micrographs of steel reinforcements (a) bare (b) in SAMPLE 1 and (c) in SAMPLE 2

steel rebar occurred due to the continuous contact of thecontaminated concrete pore solution It was noticed that thesurface of steel reinforcement in SAMPLE 2 contains littleor no oxide Thus the ability of SLS to prevent the steelreinforcement corrosion in contaminated concrete was onceagain proven by this analysis

37 Mechanism of Inhibition Sodium lauryl sulphate is asurfactant molecule and can performwell on the steel surfaceto decrease the rate of anodic and cathodic processes ofcorrosion [36 37] It can be assumed that SLS moleculespresent in concrete pore solution slowly migrate towards thesteel surface andmake coordinate bondswith the ferrous ionson the surface through the polar end Since SLS has a longhydrophobic chain pointing away from the steel surface itcan repel watermolecules and chloride ions diffusing towardsthe surface This process is really beneficial to control theelectrochemical process of corrosion In other words SLSefficiently resists the conversion of ferrous ions into hydratedferric oxide (rust) The overall mechanism of the inhibitionand the structure of SLS are represented in Figure 8

4 Conclusion

Investigations revealed that sodium lauryl sulphate has been apotent corrosion inhibitor for the steel reinforcement in con-taminated concrete for a long time Electrochemical studiesproved that the corrosion inhibition efficacy of SLS did notalter appreciably SLS generally affect the cathodic and anodicprocess of corrosion According to gravimetric studies SLSdisplayed 86 of corrosion inhibition efficiency on steelreinforcement in contaminated concrete These results arein good agreement with the electrochemical investigationresults FT-IR and microscopic surface analysis proved theinteraction of SLS on steel reinforcement

Data Availability

No data were used to support this study

Conflicts of Interest

The authors declare that they have no conflicts of interest


ONaSO

O（3(（2)10（2O

(a)

water chloride

(b)

water chloride

(c)

Figure 8 (a) Structure of sodium lauryl sulphate (b) SAMPLE 1 watermolecules and chloride ions are attached on steel surface (c) SAMPLE2 coordinated SLS prevent the migration of water molecules and chloride ions towards steel surface

References

[1] W Li C Xu S Ho B Wang and G Song ldquoMonitoringConcrete Deterioration Due to Reinforcement Corrosion byIntegrating Acoustic Emission and FBG Strain MeasurementsrdquoSensors vol 17 no 3 p 657 2017

[2] S Ahmad ldquoReinforcement corrosion in concrete structures itsmonitoring and service life predictionmdasha reviewrdquo Cement andConcrete Composites vol 25 no 4-5 pp 459ndash471 2003

[3] P C Aıtcin ldquoThe durability characteristics of high performanceconcrete a reviewrdquoCement andConcrete Composites vol 25 no4-5 pp 409ndash420 2003

[4] S Altoubat M Maalej and F U A Shaikh ldquoLaboratorySimulation of Corrosion Damage in Reinforced ConcreterdquoInternational Journal of Concrete Structures and Materials vol10 no 3 pp 383ndash391 2016

[5] M F Montemor M P Cunha M G Ferreira and A MSimoes ldquoCorrosion behaviour of rebars in fly ash mortarexposed to carbon dioxide and chloridesrdquoCement and ConcreteComposites vol 24 no 1 pp 45ndash53 2002

[6] B Reddy G K Glass P J Lim and N R Buenfeld ldquoOnthe corrosion risk presented by chloride bound in concreterdquoCement and Concrete Composites vol 24 no 1 pp 1ndash5 2002

[7] S Nesic J Postlethwaite and S Olsen ldquoAn ElectrochemicalModel for Prediction of Corrosion of Mild Steel in AqueousCarbon Dioxide Solutionsrdquo Corrosion vol 52 no 4 pp 280ndash294 1996

[8] G I Ogundele and W E White ldquoSome Observations on Cor-rosion of Carbon Steel in Aqueous Environments ContainingCarbon Dioxiderdquo Corrosion vol 42 no 2 pp 71ndash78 1986

[9] S M AbdEl Haleem S Abd ElWanees E E Abd El Aal and ADiab ldquoEnvironmental factors affecting the corrosion behaviorof reinforcing steel II Role of some anions in the initiation andinhibition of pitting corrosion of steel in Ca(OH)2 solutionsrdquoCorrosion Science vol 52 no 2 pp 292ndash302 2010

[10] SM AbdEl Haleem S AbdElWanees E E AbdEl Aal andADiab ldquoEnvironmental factors affecting the corrosion behaviorof reinforcing steel IVVariation in the pitting corrosion currentin relation to the concentration of the aggressive and theinhibitive anionsrdquo Corrosion Science vol 52 no 5 pp 1675ndash1683 2010

[11] M S Darmawan ldquoPitting corrosion model for reinforcedconcrete structures in a chloride environmentrdquo Magazine ofConcrete Research vol 62 no 2 pp 91ndash101 2010

[12] M S Anwar B Fadillah A Nikitasari S Oediyani and EMabruri ldquoStudy of Pitting Resistance of Rebar Steels in JakartaCoastal Using Simulated Concrete Pore Solutionrdquo ProcediaEngineering vol 171 pp 517ndash525 2017

[13] J G Cabrera ldquoDeterioration of concrete due to reinforcementsteel corrosionrdquo Cement and Concrete Composites vol 18 no 1pp 47ndash59 1996

[14] X G Feng G H Dong and J Y Fan ldquoEffectiveness ofan inorganic corrosion inhibitor in pore solution containingsodium chloriderdquo Applied Mechanics and Materials vol 556-562 pp 158ndash161 2014

[15] A U Malik I Andijani F Al-Moaili and G Ozair ldquoStudies onthe performance ofmigratory corrosion inhibitors in protectionof rebar concrete in Gulf seawater environmentrdquo Cement andConcrete Composites vol 26 no 3 pp 235ndash242 2004

[16] A M Vaysburd and P H Emmons ldquoCorrosion inhibitorsand other protective systems in concrete repair concepts ormisconceptsrdquo Cement and Concrete Composites vol 26 no 3pp 255ndash263 2004

[17] H Oranowska and Z Szklarska-Smialowska ldquoAn electrochem-ical and ellipsometric investigation of surface films grown oniron in saturated calcium hydroxide solutions with or withoutchloride ionsrdquoCorrosion Science vol 21 no 11 pp 735ndash747 1981

[18] C Cao ldquoOn electrochemical techniques for interface inhibitorresearchrdquoCorrosion Science vol 38 no 12 pp 2073ndash2082 1996


[19] S Qian and D Cusson ldquoElectrochemical evaluation of the per-formance of corrosion-inhibiting systems in concrete bridgesrdquoCement and Concrete Composites vol 26 no 3 pp 217ndash2332004

[20] U Angst B Elsener C K Larsen and Oslash Vennesland ldquoCriticalchloride content in reinforced concretemdasha reviewrdquoCement andConcrete Research vol 39 no 12 pp 1122ndash1138 2009

[21] S A Al-Saleh ldquoAnalysis of total chloride content in concreterdquoCase Studies in Construction Materials vol 3 pp 78ndash82 2015

[22] A Welle J D Liao K Kaiser M Grunze U Mader and NBlank ldquoInteractions of NN1015840-dimethylaminoethanol with steelsurfaces in alkaline and chlorine containing solutionsrdquo AppliedSurface Science vol 119 no 3-4 pp 185ndash190 1997

[23] A Krolikowski and J Kuziak ldquoImpedance study on calciumnitrite as a penetrating corrosion inhibitor for steel in concreterdquoElectrochimica Acta vol 56 no 23 pp 7845ndash7853 2011

[24] F Wombacher U Maeder and B Marazzani ldquoAminoalcoholbased mixed corrosion inhibitorsrdquo Cement and Concrete Com-posites vol 26 no 3 pp 209ndash216 2004

[25] C K Nmai ldquoMulti-functional organic corrosion inhibitorrdquoCement and Concrete Composites vol 26 no 3 pp 199ndash2072004

[26] J M Gaidis ldquoChemistry of corrosion inhibitorsrdquo Cement andConcrete Composites vol 26 no 3 pp 181ndash189 2004

[27] P Montes T W Bremner and D H Lister ldquoInfluence ofcalcium nitrite inhibitor and crack width on corrosion of steelin high performance concrete subjected to a simulated marineenvironmentrdquo Cement and Concrete Composites vol 26 no 3pp 243ndash253 2004

[28] M A Asaad M Ismail M M Tahir G F Huseien P B Rajaand Y P Asmara ldquoEnhanced corrosion resistance of reinforcedconcrete Role of emerging eco-friendly Elaeis guineensissilvernanoparticles inhibitorrdquo Construction and Building Materialsvol 188 pp 555ndash568 2018

[29] M G L Annaamalai G Maheswaran N Ramesh C KamalG Venkatesh and P Vennila ldquoInvestigation of CorrosionInhibition of Welan Gum and Neem Gum on Reinforcing SteelEmbedded in Concreterdquo International Journal of Electrochemi-cal Science vol 13 pp 9981ndash9998 2018

[30] A Kumar ldquoCorrosion Inhibition of Mild Steel in HydrochloricAcid by Sodium Lauryl Sulfate (SLS)rdquo E-Journal of Chemistryvol 5 Article ID 574343 6 pages 2008

[31] M L Cedeno L E Vera and T Y Pineda ldquoA study ofcorrosion inhibition of steel AISI-SAE 1020 inCO2 -brine usingsurfactant Tween 80rdquo Journal of Physics Conference Series vol786 Article ID 12038 2017

[32] H J Flitt and D P Schweinsberg ldquoEvaluation of corrosionrate from polarisation curves not exhibiting a Tafel regionrdquoCorrosion Science vol 47 no 12 pp 3034ndash3052 2005

[33] J Chen and X Zhang ldquoAC impedance spectroscopy analysisof the corrosion behavior of reinforced concrete in chloridesolutionrdquo International Journal of Electrochemical Science vol12 no 6 pp 5036ndash5043 2017

[34] D V Ribeiro C A C Souza and J C C Abrantes ldquoUse ofElectrochemical Impedance Spectroscopy (EIS) to monitoringthe corrosion of reinforced concreterdquo Revista IBRACON deEstruturas e Materiais vol 8 no 4 pp 529ndash546 2015

[35] K V S Ramana S Kaliappan N Ramanathan and V KavithaldquoCharacterization of rust phases formed on low carbon steelexposed to natural marine environment of Chennai harbour -South Indiardquo Materials and Corrosion vol 58 no 11 pp 873ndash880 2007

[36] T Zhao andGMu ldquoThe adsorption and corrosion inhibition ofanion surfactants on aluminium surface in hydrochloric acidrdquoCorrosion Science vol 41 no 10 pp 1937ndash1944 1999

[37] Y Zhu M L Free R Woollam and W Durnie ldquoA review ofsurfactants as corrosion inhibitors and associated modelingrdquoProgress in Materials Science vol 90 pp 159ndash223 2017

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SS mesh

ElectrochemicalWorkstation

Rebar

Wet sponge

SCE

Figure 1 Three-electrode circuitry for electrochemical studies

in contaminated concrete [30 31] Preliminary examina-tions were done by measuring the electrode potentials ofsteel reinforcements (against SCE) dipped in concrete poresolution contaminated with 35 NaCl containing variousconcentrations of SLS After this examination we decidedto investigate the corrosion response of steel reinforcementin concrete specimen containing 25 of SLS by weight ofcement

2 Experimental

21 Materials Sodium lauryl sulphate and sodium chloride(gt999 ) were procured from Merck Millipore Portlandcement (Indiana Cements Grade 53) used for making con-crete specimens was purchased from the market

22 Preparation of Concrete Test Specimens Concrete blockscontaining steel reinforcement used for the experiment weremade of Portland cement coarse aggregate fine aggregate(sand) and water Each rectangular block having dimensionof 200x80x80mm was prepared by mixing water and cementin the ratio 05The ratio between cement fine aggregate andcoarse aggregate was 1153 which will exactly mimic M-20grade concrete SLS was added to the concrete mixture by25 wt of cement and two test specimens were casted Inthis work we designate the concrete specimen without SLSas SAMPLE 1 and with SLS as SAMPLE 2 The approximatecomposition of steel rod was estimated by EDAXmethod 01 P 062 Mn 0021 Si 004 S and rest Fe Steel rebarswere cut (22 cm) and immersed in 2M HCl for 10 minutesfor removing the rust washed with distilled water degreasedwith acetone dried weighed and used as the reinforcementin concrete After a period of 24 h the test specimens wereremoved from themould and cured for 30 days for the properhydration and setting of the cement

23 Treatment of Test Specimens After the curing periodfive sides of the test specimens were coated with epoxyresin and one open reservoir (100x40x20mm) was built onthe remaining side with polypropylene and silicon adhesive

25mL 35NaCl was added to the reservoir of the specimensand kept for 2 days This will ensure the complete diffusionof NaCl throughout the specimen This process was repeatedthree times during 30-60 days

24 Electrochemical Investigations

(i) Potentiodynamic Polarization Studies Figure 1 shows theschematic diagram of the test specimen and the experi-mental setup for electrochemical studies Three-electrodecell assembly consisting of steel reinforcement present inconcrete as working electrode concrete specimen coveredwith a stainless steel mesh as counter electrode and saturatedcalomel electrode (SCE) as reference electrode were used forthe electrochemical studies [32] For good electrical contacta wet sponge was used on the concrete surface between SCEand concrete surface

After curing and treatment of test specimens with NaClpolarization studies were performed three times during aperiod of 480 days in 160 daysrsquo interval Steel reinforcement inthe concrete was scanned for a potential range of +250 to -250mV having a scan rate of 1mVs Tafel curves were analyzedto get the slopes which are extrapolated to get the corrosioncurrent densities The corrosion inhibition efficiency of SLSwas determined using the following equation

120578pol =119868corr minus 119868

1015840

corr119868corr

X100 (1)

where Icorr and I1015840corr are corrosion current densities of steelreinforcement in test specimens in the absence and presenceof SLS respectively Experiments were repeated with theduplicate concrete block and the average values were taken

(ii) Electrochemical Impedance Spectroscopic (EIS) Studies EISexperiments were carried out at constant potential in thefrequency range of 1 KHz to 100 mHz with excitation signalof 10mV amplitude Analysis of the Nyquist curves using theequivalent circuit gave the charge transfer resistance (Rct)




SAMPLE 2 18 430 232 573 89320 SAMPLE 1 139 489 156 662

SAMPLE 2 41 469 229 520 71480 SAMPLE 1 107 373 215 551

SAMPLE 2 21 341 230 561 80



RctX100 (2)




120578 = 1199080 minus 1199081199080

times 100 (3)


1 and SAMPLE 2








Sample 1



Potential (V)

minus25

minus20

minus15

minus10

minus05

00

05

10

15

log

curr

ent d

ensit

y(Ac

m

)

(a)

Sample 2



Potential(V)

minus35

minus30

minus25

minus20

minus15

minus10

minus05

00

05

10

log

curr

ent d

ensit

y(Ac

m

)

(b)




SAMPLE 2 502 975 109 931 872320 SAMPLE 1 352 157 885 147

SAMPLE 2 927 459 42 665 78480 SAMPLE 1 323 223 273 243

SAMPLE 2 158 574 096 173 86









2

3

1

2 3

1

1 160 days

Sample 1

Sample 2



00

05

10

15

20

25

30

minusZ

(o

hm cＧ

2)

15 20 25 3010Z

(ohm cＧ2)

0

5

10

15

20

25

30

35

40

minusZ

(o

hm cＧ

2)

60 180 100 120 140 160 180 200 22040Z

(ohm cＧ2)

(a)

2 3

3

1

21

Sample 1

Sample 2



12 14 16 18 20 22 24 26 28 301010log(frequency)Hz

0

200

400

600

800

1000

10lo

gZo

hm

0

200

400

600

800

1000

10lo

gZo

hm

60 180 100 120 140 160 180 2004010log(frequency)Hz

(b)


Rs

W

Cdl

Rct







Table3Halfcellp

otentia

l(mV)o

fsteelreinforcem

entinconcretein

thep

resencea

ndabsenceo

fSLS

for4

80days

Day

3060

90120

150

180

210

240

270

300

330

360

390

420

450

480

SAMPL

E1

-607

-588

-580

-555

-560

-554

-567

-578

-611

-592

-625

-628

-589

-602

-597

-600

SAMPL

E2

-416

-463

-420

-423

-514

-457

-497

-473

-440

-416

-499

-516

-535

-399

-397

-389


Sample 1Sample 2

100 200 300 400 5000Days

minus650

minus600

minus550

minus500

minus450

minus400

Hal

f cel

l pot

entia

l



3000 2000 1000 04000

3375

4411471

638

1619

868

1350


minus50

0

50

100

150

200

250

300

350

400

T

rans

mitt

ance

(a)

3349

2895

28022347

16331420

1104955

789

2922

2821

16521466

1244

1067984

826


4000 25003500 50020003000 10001500Wavenumber cＧ-1

minus10

0

10

20

30

40

50

60

70

80

90

100

110

T

rans

mitt

ance

SLS

2376

(b)








(a) (b)

(c)




4 Conclusion


Data Availability





ONaSO

O（3(（2)10（2O

(a)

water chloride

(b)

water chloride

(c)


References









































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls







SAMPLE 2 18 430 232 573 89320 SAMPLE 1 139 489 156 662

SAMPLE 2 41 469 229 520 71480 SAMPLE 1 107 373 215 551

SAMPLE 2 21 341 230 561 80



RctX100 (2)




120578 = 1199080 minus 1199081199080

times 100 (3)


1 and SAMPLE 2








Sample 1



Potential (V)

minus25

minus20

minus15

minus10

minus05

00

05

10

15

log

curr

ent d

ensit

y(Ac

m

)

(a)

Sample 2



Potential(V)

minus35

minus30

minus25

minus20

minus15

minus10

minus05

00

05

10

log

curr

ent d

ensit

y(Ac

m

)

(b)




SAMPLE 2 502 975 109 931 872320 SAMPLE 1 352 157 885 147

SAMPLE 2 927 459 42 665 78480 SAMPLE 1 323 223 273 243

SAMPLE 2 158 574 096 173 86









2

3

1

2 3

1

1 160 days

Sample 1

Sample 2



00

05

10

15

20

25

30

minusZ

(o

hm cＧ

2)

15 20 25 3010Z

(ohm cＧ2)

0

5

10

15

20

25

30

35

40

minusZ

(o

hm cＧ

2)

60 180 100 120 140 160 180 200 22040Z

(ohm cＧ2)

(a)

2 3

3

1

21

Sample 1

Sample 2



12 14 16 18 20 22 24 26 28 301010log(frequency)Hz

0

200

400

600

800

1000

10lo

gZo

hm

0

200

400

600

800

1000

10lo

gZo

hm

60 180 100 120 140 160 180 2004010log(frequency)Hz

(b)


Rs

W

Cdl

Rct







Table3Halfcellp

otentia

l(mV)o

fsteelreinforcem

entinconcretein

thep

resencea

ndabsenceo

fSLS

for4

80days

Day

3060

90120

150

180

210

240

270

300

330

360

390

420

450

480

SAMPL

E1

-607

-588

-580

-555

-560

-554

-567

-578

-611

-592

-625

-628

-589

-602

-597

-600

SAMPL

E2

-416

-463

-420

-423

-514

-457

-497

-473

-440

-416

-499

-516

-535

-399

-397

-389


Sample 1Sample 2

100 200 300 400 5000Days

minus650

minus600

minus550

minus500

minus450

minus400

Hal

f cel

l pot

entia

l



3000 2000 1000 04000

3375

4411471

638

1619

868

1350


minus50

0

50

100

150

200

250

300

350

400

T

rans

mitt

ance

(a)

3349

2895

28022347

16331420

1104955

789

2922

2821

16521466

1244

1067984

826


4000 25003500 50020003000 10001500Wavenumber cＧ-1

minus10

0

10

20

30

40

50

60

70

80

90

100

110

T

rans

mitt

ance

SLS

2376

(b)








(a) (b)

(c)




4 Conclusion


Data Availability





ONaSO

O（3(（2)10（2O

(a)

water chloride

(b)

water chloride

(c)


References









































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





Sample 1



Potential (V)

minus25

minus20

minus15

minus10

minus05

00

05

10

15

log

curr

ent d

ensit

y(Ac

m

)

(a)

Sample 2



Potential(V)

minus35

minus30

minus25

minus20

minus15

minus10

minus05

00

05

10

log

curr

ent d

ensit

y(Ac

m

)

(b)




SAMPLE 2 502 975 109 931 872320 SAMPLE 1 352 157 885 147

SAMPLE 2 927 459 42 665 78480 SAMPLE 1 323 223 273 243

SAMPLE 2 158 574 096 173 86









2

3

1

2 3

1

1 160 days

Sample 1

Sample 2



00

05

10

15

20

25

30

minusZ

(o

hm cＧ

2)

15 20 25 3010Z

(ohm cＧ2)

0

5

10

15

20

25

30

35

40

minusZ

(o

hm cＧ

2)

60 180 100 120 140 160 180 200 22040Z

(ohm cＧ2)

(a)

2 3

3

1

21

Sample 1

Sample 2



12 14 16 18 20 22 24 26 28 301010log(frequency)Hz

0

200

400

600

800

1000

10lo

gZo

hm

0

200

400

600

800

1000

10lo

gZo

hm

60 180 100 120 140 160 180 2004010log(frequency)Hz

(b)


Rs

W

Cdl

Rct







Table3Halfcellp

otentia

l(mV)o

fsteelreinforcem

entinconcretein

thep

resencea

ndabsenceo

fSLS

for4

80days

Day

3060

90120

150

180

210

240

270

300

330

360

390

420

450

480

SAMPL

E1

-607

-588

-580

-555

-560

-554

-567

-578

-611

-592

-625

-628

-589

-602

-597

-600

SAMPL

E2

-416

-463

-420

-423

-514

-457

-497

-473

-440

-416

-499

-516

-535

-399

-397

-389


Sample 1Sample 2

100 200 300 400 5000Days

minus650

minus600

minus550

minus500

minus450

minus400

Hal

f cel

l pot

entia

l



3000 2000 1000 04000

3375

4411471

638

1619

868

1350


minus50

0

50

100

150

200

250

300

350

400

T

rans

mitt

ance

(a)

3349

2895

28022347

16331420

1104955

789

2922

2821

16521466

1244

1067984

826


4000 25003500 50020003000 10001500Wavenumber cＧ-1

minus10

0

10

20

30

40

50

60

70

80

90

100

110

T

rans

mitt

ance

SLS

2376

(b)








(a) (b)

(c)




4 Conclusion


Data Availability





ONaSO

O（3(（2)10（2O

(a)

water chloride

(b)

water chloride

(c)


References









































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





2

3

1

2 3

1

1 160 days

Sample 1

Sample 2



00

05

10

15

20

25

30

minusZ

(o

hm cＧ

2)

15 20 25 3010Z

(ohm cＧ2)

0

5

10

15

20

25

30

35

40

minusZ

(o

hm cＧ

2)

60 180 100 120 140 160 180 200 22040Z

(ohm cＧ2)

(a)

2 3

3

1

21

Sample 1

Sample 2



12 14 16 18 20 22 24 26 28 301010log(frequency)Hz

0

200

400

600

800

1000

10lo

gZo

hm

0

200

400

600

800

1000

10lo

gZo

hm

60 180 100 120 140 160 180 2004010log(frequency)Hz

(b)


Rs

W

Cdl

Rct







Table3Halfcellp

otentia

l(mV)o

fsteelreinforcem

entinconcretein

thep

resencea

ndabsenceo

fSLS

for4

80days

Day

3060

90120

150

180

210

240

270

300

330

360

390

420

450

480

SAMPL

E1

-607

-588

-580

-555

-560

-554

-567

-578

-611

-592

-625

-628

-589

-602

-597

-600

SAMPL

E2

-416

-463

-420

-423

-514

-457

-497

-473

-440

-416

-499

-516

-535

-399

-397

-389


Sample 1Sample 2

100 200 300 400 5000Days

minus650

minus600

minus550

minus500

minus450

minus400

Hal

f cel

l pot

entia

l



3000 2000 1000 04000

3375

4411471

638

1619

868

1350


minus50

0

50

100

150

200

250

300

350

400

T

rans

mitt

ance

(a)

3349

2895

28022347

16331420

1104955

789

2922

2821

16521466

1244

1067984

826


4000 25003500 50020003000 10001500Wavenumber cＧ-1

minus10

0

10

20

30

40

50

60

70

80

90

100

110

T

rans

mitt

ance

SLS

2376

(b)








(a) (b)

(c)




4 Conclusion


Data Availability





ONaSO

O（3(（2)10（2O

(a)

water chloride

(b)

water chloride

(c)


References









































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





Table3Halfcellp

otentia

l(mV)o

fsteelreinforcem

entinconcretein

thep

resencea

ndabsenceo

fSLS

for4

80days

Day

3060

90120

150

180

210

240

270

300

330

360

390

420

450

480

SAMPL

E1

-607

-588

-580

-555

-560

-554

-567

-578

-611

-592

-625

-628

-589

-602

-597

-600

SAMPL

E2

-416

-463

-420

-423

-514

-457

-497

-473

-440

-416

-499

-516

-535

-399

-397

-389


Sample 1Sample 2

100 200 300 400 5000Days

minus650

minus600

minus550

minus500

minus450

minus400

Hal

f cel

l pot

entia

l



3000 2000 1000 04000

3375

4411471

638

1619

868

1350


minus50

0

50

100

150

200

250

300

350

400

T

rans

mitt

ance

(a)

3349

2895

28022347

16331420

1104955

789

2922

2821

16521466

1244

1067984

826


4000 25003500 50020003000 10001500Wavenumber cＧ-1

minus10

0

10

20

30

40

50

60

70

80

90

100

110

T

rans

mitt

ance

SLS

2376

(b)








(a) (b)

(c)




4 Conclusion


Data Availability





ONaSO

O（3(（2)10（2O

(a)

water chloride

(b)

water chloride

(c)


References









































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





Sample 1Sample 2

100 200 300 400 5000Days

minus650

minus600

minus550

minus500

minus450

minus400

Hal

f cel

l pot

entia

l



3000 2000 1000 04000

3375

4411471

638

1619

868

1350


minus50

0

50

100

150

200

250

300

350

400

T

rans

mitt

ance

(a)

3349

2895

28022347

16331420

1104955

789

2922

2821

16521466

1244

1067984

826


4000 25003500 50020003000 10001500Wavenumber cＧ-1

minus10

0

10

20

30

40

50

60

70

80

90

100

110

T

rans

mitt

ance

SLS

2376

(b)








(a) (b)

(c)




4 Conclusion


Data Availability





ONaSO

O（3(（2)10（2O

(a)

water chloride

(b)

water chloride

(c)


References









































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





(a) (b)

(c)




4 Conclusion


Data Availability





ONaSO

O（3(（2)10（2O

(a)

water chloride

(b)

water chloride

(c)


References









































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





ONaSO

O（3(（2)10（2O

(a)

water chloride

(b)

water chloride

(c)


References









































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls


























Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls




prevention of reinforcement corrosion in concrete by sodium … · 2019. 7. 30. · prevention of...

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