Hydration kinetics modeling of Portland cement considering the effects of curing temperature and applied pressure

a r t i c l e i n f o A hydration kinetics model for Portland cement is formulated based on thermodynamics of multiphase porous media. The mechanism of cement hydration is discussed based on literature review. The model is then developed considering the effects of chemical composition and fineness of cement, water–cement ratio, curing temperature and applied pressure. The ultimate degree of hydration of Portland cement is also analyzed and a corresponding formula is established. The model is calibrated against the experimental data for eight different Portland cements. Simple relations between the model parameters and cement composition are obtained and used to predict hydration kinetics. The model is used to reproduce experimental results on hydration kinetics, adiabatic temperature rise, and chemical shrinkage of different cement pastes. The comparisons between the model reproductions and the different experimental results demonstrate the applicability of the proposed model, especially for cement hydration at elevated temperature and high pressure. The hydration of cement and the accompanying phenomena such as heat generation, strength development and shrinkage are the results of interrelated chemical, physical and mechanical processes. A thorough understanding of theses processes is a critical prerequisite for modeling hydration kinetics of cementitious materials. The advances of computer technology made it possible for a branch of computational materials science to develop rapidly in the past twenty years, i.e., the computer modeling of hydration and micro-structure development of concrete. Noteworthy studies include those of Jennings and Johnson [1], Bentz and Garboczi [2], van Breugel [3], Navi and Pignat [4], and Maekawa et al. [5]. Among these, the NIST model, referred to as CEMHYD3D [6], and the HYMOSTRUC model [3] appear to be the most advanced and widely used ones. These models attempt to simulate cement hydration and microstructure formation on the elementary level of cement particles, which is the most rational way, as long as the chemical, physical and mechanical characteristics of cement hydration are properly taken into account. However, there exist certain applications for which simpler mathematical models describing and quantifying hydration kinetics are necessary. In fact, numerous attempts have been undertaken with that objective and many such simplified formulations can be found in In contrast to the aforementioned microscopic models, most of these simplified models are empirical in nature, based on experimental observations of macroscopic phenomena, and they capture the effects of curing temperature, water–cement ratio, fineness, particle size distribution and chemical composition of …