Experimental and theoretical studies of hydration of ultra-high performance concrete cured under various curing conditions

Abstract

The hydration of UHPC from 1 to 180 days was experimentally and theoretically studied. Three different curing regimes were employed during the sample preparation process in order to observe their effects on the hydration and reaction products. The samples were experimentally characterized, and the experimentally obtained degrees of the reaction of the cement and amorphous silica in the UHPC samples were used for thermodynamic calculations to predict the phase assemblages of UHPC. The decomposition of AFt phases occurred in the sample that underwent a heat treatment, which also resulted in Alsubstitution for Si in C-S-H gels. The degree of the reaction of the cement and amorphous silica varied greatly depending on the curing condition applied during the first few days, and higher reaction degree was observed in the heat-treated sample, which showed a significant amount of C-S-H present at an early age, making its microstructure denser than those of the other samples. (C) 2021 Elsevier Ltd. All rights reserved.