Decoupling the Effect of Aggregates on Pore Solution Composition and Electrical Properties of Concrete

The alkalinity of concrete has long been recognized as an important factor in alkali-silica reaction (ASR). The introduction of electrical resistivity for evaluating ASR potential adds a new dimension of importance to the role of alkalis that are the primary conductive ions in concrete. A sand with a high alkali affinity and a non-reactive sand were used in this study. High-pressure extraction was done to obtain pore solution for analyses by XRF. The electrical resistivity of the hardened mortars and extracted solutions was measured. The effect of aggregate absorption capacities on the pore solution concentrations was accounted for using a pore partitioning model (PPM) to help isolate the influence of aggregates on alkalinity. The capability of aggregate to adsorb alkali in hardened mortars was supported by the results .