The prediction model of concrete carbonation depth based on cement hydration

Based on the periodic boundary conditions,an improved numerical cement hydration model is es-tablished in this paper to precisely predict the time varying development of carbonation depth in concrete.Three parameters, including the interfered degrees of unhydrated cement layer,hydration product lay-er and air layer of central cement grains during the hydration process,are introduced to quantitatively rep-resent the interference effect between cement particles. Considering the influence of cement mineral composi-tions,water to cement ratio(w/c),particle size distribution on cement hydration process,the developmentof hydration degree,porosity and hydration products with age are analyzed. Based on the prediction modelof carbonation depth in concrete established by Papadakis,a method for predicting the carbonation depthin concrete is proposed in considering cement hydration. The standard carbonation test method was used toverify the model proposed in this research. It can be seen from the experimental research that the numeri-cal simulation results agree well with the experiment. And the prediction model of carbonation depth estab-lished in this research is of great importance to the durability investigation of concrete.