Effect of the interfacial transition zone on the transport and the elastic properties of mortar

Abstract

In order to investigate the effect of aggregate content and interfacial transition zone (ITZ) on the transport properties of mortar, specimens with different fine aggregate volume fractions were cast and tested. The chloride ion migration coefficient and the total chloride content of mortars were obtained using the accelerated chloride migration test and the experimental results were plotted as a function of the fine aggregate volume fraction. The results were analysed using the regression models that represent mortar as a three-phase composite material (cement paste, fine aggregate and ITZ) to estimate the transport properties of ITZ. The elastic modulus of ITZ was obtained using micromechanics method and experimental results. Based on the experimental and regression analytical results, when the assumed thickness of ITZ is 20 μm, the chloride content, chloride migration coefficient and elastic modulus of ITZ are 1·8, 1·6 and 0·2–0·4 times of the matrix properties, respectively.