Phase field simulation of early-age fracture in cement-based materials

In this paper, a new computational approach, which is based on a multi-physics coupling of the chemo-thermo-mechanical process, is developed for modeling failure mechanism in cement-based materials at early-age hydration. A new constitutive law describing mechanical behavior of young concrete is thus derived, taking into account the effects of several factors including thermal expansion, shrinkage, damage, and both basic and transient thermal creeps. A strongly coupled model describing the interaction between fracture and multi-physics problems of cement hydration is obtained. The present phase field model in terms of smeared crack approach is highly suitable for simulating crack, especially when considering the unilateral contact conditions at crack surfaces. The capability of the proposed model in modeling complex crack initiation and propagation under arbitrary boundary conditions is highlighted. Fracture phenomena at both macroscopic and mesoscopic scales are considered and analyzed. The effects of creep and microstructural heterogeneity in different length scale are investigated, showing the great potential of the developed approach.