Water Absorption and Electrical Conductivity for Internally Cured Mortars with a W/C between 0.30 and 0.45

Abstract

Internal curing has emerged over the last decade as an approach to counteract the negative effects associated with self-desiccation in low water-to-cement ratio (w/c) mixtures. Specifically, much of the early research on internal curing focused on the reduction of autogenous shrinkage. Recent work has demonstrated, however, that internal curing can also be beneficial in reducing drying-shrinkage cracking, reducing the propensity for thermal cracking, reducing fluid absorption, and reducing ion diffusion in concrete. However, several aspects of internal curing still require closer examination. One of these aspects is the application of internal curing for mixtures with a wider range of water-to-cement ratios. This paper describes results from experiments that investigated the potential use of internal curing in mortar systems with w/c ratios of 0.30, 0.36, 0.42, and 0.45 that were cured under sealed conditions, in terms of water absorption and electrical conductivity. Test results show that internal curing reduces the water absorption in all the systems. Similarly, results obtained on electrical conductivity at late ages (1 year) also show a benefit. Care needs to be taken to analyze electrical conductivity results at early ages because of the increased amount of fluid resulting from the inclusion of the prewetted lightweight aggregate.