A Peak in the hydration reaction at the end of the cement induction period

Although the hydration of ordinary Portland cement (OPC) and its main constitutent, tricalcium silicate (3CaO.SiO2 or C3S), have been studied for many decades, some aspects of the hydration process remain poorly understood. In particular, there is little consensus on the mechanisms related to the dormant or induction period. The induction period is a time of minimal hydration activity between the initial hydration reactions upon wetting and the later priamry tricalcium silicate reaction with water to form calcium silicate hydrate and calcium hydroxide. This letter examines the mechanisms responsible for a peak in hydration activity at the end of the induction period. Although occasionally seen in the literature, this peak appears absent in most reported measurements and has therefore remained unexplained.Peer reviewed: YesNRC publication: Ye