Relations among electrical resistivity, chemical and autogenous shrinkage of cement pastes

Electrical resistivity, chemical shrinkage and autogenous shrinkage were measured for cement pastes with different water to binder (w/b) ratios (0·30, 0·35 and 0·40) and fly ash replacements of cement (0%, 30% and 50%). The electrical resistivity, chemical shrinkage and autogenous shrinkage of the pastes decreased with increasing w/b ratio and fly ash content after final setting. The autogenous shrinkage development over time could be divided into a setting period, a rapid growth period, an expansion period and a slow growth period. Based on the test results, the chemical shrinkage and the autogenous shrinkage were linearly correlated to electrical resistivity after hydration for 24 h and 30 h respectively. The linear relationships will help to expand the application of electrical resistivity measurements. The parameter γ, defined as the proportion of autogenous shrinkage to linear chemical shrinkage after the final set, decreased with time due to increasing paste stiffness. This parameter will help researchers quantitatively understand the volume proportion of autogenous shrinkage and empty cavities during hydration.