Mathematical models for degree of hydration, moisture and temperature distributions in early age concrete

The degree of hydration is a major parameter to control the chemical and physical processes in concrete. Therefore, it is necessary that material parameters and microstructure development be formulated in terms of the degree of hydration. The present study introduces realistic material laws and models to describe early age behavior of concrete. A 3D finite element procedure was formulated to evaluate the degree of hydration, temperature and moisture distributions in hardening concrete. The mathematical formulation of degree of hydration is based on the combination of three rate functions of reaction. Moisture parameters were considered to be age-dependent. Prediction of moisture sink due to the hydration process, i.e. selfdesiccation, is related to autogenous shrinkage. The proposed models agree well with test data on the moisture and temperature distributions of concrete at early ages.