Multiphysics simulation for concrete early-age hydration behavior with mesoscopic modelling

Abstract

The early-age hydration behavior of concrete is of great significance for structural construction and service performance. Hydration is a complex multiphysics process coupling the field of chemical reaction, humidity transport, heat conductivity, and mechanical response. The random distribution of different phases in the material has a marked impact on hydration, and the material’s mesoscopic feature is also important for the accurate prediction of concrete hydration behavior. Combining the material mesoscopic feature and multiphysics hydration mechanism, a comprehensive theoretical framework is proposed with detailed material modelling and physics coupling relationship in this paper. Besides the overall simulation procedure, the study on model modification methods for different curing environments and different concrete materials, especially the influence of expansion additives, is also conducted. Based on the application of concrete material and specified expansion agent in engineering, experiments are carried out to investigate the hydration process and mechanical shrinkage of concrete. The results are used for parameter regression and model validation. With the model's advantages in describing multiphysics influence and the mesoscopic features, the detailed time-dependent hydration process and spatial distribution of related physics can be simulated precisely and conveniently. At last, the influences of environmental states and mixing parameters on concrete hydration behavior are investigated, and the control of curing humidity and aggregate details is found necessary.