Assessment of Concrete Durability by Surface Resistivity and Initial Surface Absorption

Abstract

AbstractPerformance-based durability design has gained considerable attention in the construction industry for the service life-based designs of new constructions. Currently, prescriptive-type specifications are used in durability design to meet the service life requirements which prescribe the constituent materials with limiting values of the concrete mix proportion and cover to reinforcement under a given exposure condition. In this context, performance requirements are assumed to be satisfied during the life span of the structure. Prescriptive specifications are valid within a selected range of the cement composition and exposure conditions of concrete, and therefore, these descriptive requirements are often not applicable in the rapidly changing concrete industry. Contrarily, in the case of performance-based durability design approach, there is more flexibility in selection and proportioning of constituent material in producing concrete to satisfy a particular exposure condition. In order to change from prescriptive specifications to performance-based design for durability of concrete, it is essential to find relevant durability indicators with appropriate test methods to evaluate those indicators. In this research, the main focus was given to evaluate two durability-related tests which are commonly used in the construction industry such as surface resistivity test and initial surface absorption test (ISAT) for concrete with the addition of fly ash as a supplementary cementitious material as a partial replacement of Ordinary Portland cement. Experimental investigations were carried out by varying the fly ash percentage, water-to-cement (w/c) ratio and curing condition. It was found that initial surface absorption and surface resistivity are having higher sensitivity toward the variation of factors affecting durability such as w/c ratio, fly ash content and curing condition and can be used as reliable concrete durability indicators.KeywordsConcrete durabilityISATSurface resistivityFly ashW/C ratioCuring condition