An investigation into the relationship between surface concrete resistivity and chloride conductivity test

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dc.contributor.advisorBeushausen, Hans-Dieteren_ZA
dc.contributor.advisorAlexander, Mark Gavinen_ZA
dc.contributor.advisorOtieno, Mikeen_ZA
dc.contributor.authorMutale, Lombeen_ZA
dc.date.accessioned2014-11-05T03:33:36Z
dc.date.available2014-11-05T03:33:36Z
dc.date.issued2014en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractThe chloride conductivity test (CCT) is a South African-developed Durability Index (DI) test used for the evaluation and quantification of the quality of concrete cover. It is also used as an input parameter for service life prediction (SLP) of RC structures in the marine environment, using a modified version of Crank’s solution to Fick’s second law of diffusion. The surface concrete resistivity test is an electrochemical test that has a good correlation with the concrete chloride diffusion process. The surface concrete resistivity test is used as a quick way to determine the durability of concrete. The purpose of this study was to provide an in-depth literature review on surface concrete resistivity and investigate its use for the design and prediction of durability in RC structures. The study also compared and contrasted surface concrete resistivity with CCT, using results from previous work, in terms of their application in the design of RC structures. Thereafter, the study investigated the relationship between surface concrete resistivity and CCT. The study was carried out by comparing laboratory and field surface concrete resistivity with CCT results. Then, corrosion initiation periods (CIP’s) and diffusion coefficients were estimated using Mackechnie’s (1996) CCT SLP model as well as surface concrete resistivity models by Andrade (2004) and Baroghel-Bouny et al. (2009). Input parameters for the model such as surface concrete resistivity and CCT results were based on measurements from a previous study. It was found that moisture gradients, chloride contamination and temperature gradients easily influence concrete electrical resistivity testing done in-situ. The input parameters for the surface concrete resistivity models were restricted to laboratory results. The analysis revealed that for blended cement concrete, w/b ratio has a greater influence on chloride conductivity than binder type. It was observed that using a different binder type has a greater influence on surface concrete resistivity at a high w/b ratio than a low one. In addition, decreasing the w/b ratio for GGBS concrete is more effective than decreasing it for FA concrete in influencing the surface concrete resistivity. Andrade’s surface concrete resistivity SLP model resulted in similar CIP values as the CCT model for CEM I only concrete and slag concrete at 0.40 w/b. A constant links the diffusion coefficients from surface concrete resistivity and CCT models. An inverse relationship was found between surface concrete resistivity and the diffusion coefficient calculated from the CCT SLP model.en_ZA
dc.identifier.apacitationMutale, L. (2014). <i>An investigation into the relationship between surface concrete resistivity and chloride conductivity test</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Civil Engineering. Retrieved from http://hdl.handle.net/11427/9077en_ZA
dc.identifier.chicagocitationMutale, Lombe. <i>"An investigation into the relationship between surface concrete resistivity and chloride conductivity test."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Civil Engineering, 2014. http://hdl.handle.net/11427/9077en_ZA
dc.identifier.citationMutale, L. 2014. An investigation into the relationship between surface concrete resistivity and chloride conductivity test. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Mutale, Lombe AB - The chloride conductivity test (CCT) is a South African-developed Durability Index (DI) test used for the evaluation and quantification of the quality of concrete cover. It is also used as an input parameter for service life prediction (SLP) of RC structures in the marine environment, using a modified version of Crank’s solution to Fick’s second law of diffusion. The surface concrete resistivity test is an electrochemical test that has a good correlation with the concrete chloride diffusion process. The surface concrete resistivity test is used as a quick way to determine the durability of concrete. The purpose of this study was to provide an in-depth literature review on surface concrete resistivity and investigate its use for the design and prediction of durability in RC structures. The study also compared and contrasted surface concrete resistivity with CCT, using results from previous work, in terms of their application in the design of RC structures. Thereafter, the study investigated the relationship between surface concrete resistivity and CCT. The study was carried out by comparing laboratory and field surface concrete resistivity with CCT results. Then, corrosion initiation periods (CIP’s) and diffusion coefficients were estimated using Mackechnie’s (1996) CCT SLP model as well as surface concrete resistivity models by Andrade (2004) and Baroghel-Bouny et al. (2009). Input parameters for the model such as surface concrete resistivity and CCT results were based on measurements from a previous study. It was found that moisture gradients, chloride contamination and temperature gradients easily influence concrete electrical resistivity testing done in-situ. The input parameters for the surface concrete resistivity models were restricted to laboratory results. The analysis revealed that for blended cement concrete, w/b ratio has a greater influence on chloride conductivity than binder type. It was observed that using a different binder type has a greater influence on surface concrete resistivity at a high w/b ratio than a low one. In addition, decreasing the w/b ratio for GGBS concrete is more effective than decreasing it for FA concrete in influencing the surface concrete resistivity. Andrade’s surface concrete resistivity SLP model resulted in similar CIP values as the CCT model for CEM I only concrete and slag concrete at 0.40 w/b. A constant links the diffusion coefficients from surface concrete resistivity and CCT models. An inverse relationship was found between surface concrete resistivity and the diffusion coefficient calculated from the CCT SLP model. DA - 2014 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2014 T1 - An investigation into the relationship between surface concrete resistivity and chloride conductivity test TI - An investigation into the relationship between surface concrete resistivity and chloride conductivity test UR - http://hdl.handle.net/11427/9077 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/9077
dc.identifier.vancouvercitationMutale L. An investigation into the relationship between surface concrete resistivity and chloride conductivity test. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Civil Engineering, 2014 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/9077en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Civil Engineeringen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.titleAn investigation into the relationship between surface concrete resistivity and chloride conductivity testen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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