Autogenous Shrinkage of Cement Paste Interpreted by Electrical Resistivity and Capillary Stress at Early Age

Abstract Autogenous shrinkage caused by the self-desiccation of cement-based materials at early age requires more attention from researchers because it can increase the risk of cracking in concrete. This article presents the relationships among autogenous shrinkage after final setting, the estimated effective capillary stress, and electrical resistivity of cement pastes. Autogenous shrinkage, internal relative humidity, chemical shrinkage, and electrical resistivity were measured for the plain cement paste that had water to cement ratios (W/C) of 0.3, 0.35, and 0.4 at early age. Electrical resistivity and its rate curve were presented to analyze the influence of W/C on the hydration process. A fitting function containing W/C, electrical resistivity, and three constant parameters was put forward to quantify the relationship between autogenous shrinkage and electrical resistivity. The autogenous shrinkage of cement paste at different ages can be predicted by the resistivity at 24 h; the relationship between electrical resistivity at 24 h and the effective capillary stress S·σcap at 24 h, 48 h, 72 h, and 96 h was also established to support the effectiveness of relating the self-desiccation development trend and electrical property of cement paste. This study introduces innovative and quick methods to estimate the autogenous shrinkage of cement paste by electrical resistivity.