Freeze-thaw damage model for cement pavements in seasonal frost regions

In order to evaluate the damage of cement concrete pavement after the freeze-thaw cycle in the seasonal frozen area, it is determined that the dynamic elastic modulus and flexural tensile strength by analyzing the influence of the freeze-thaw on the concrete performance. The two indexes are most sensitive to the evaluation of the freeze-thaw damage of the pavement. Based on regression analysis method, two freeze-thaw damage models based on two indexes are established, and the goodness of fit and significance state of the model are tested. The applicable conditions of the two models are determined by response surface test method. The validity of the model is verified by comparing the prediction results of the existing model. The results show that when the water cement ratio is 0.45-0.48, the gas content is 1% - 4%, and the freezing temperature is - 15℃ - 25℃. The model based on dynamic elastic modulus index has the best evaluation effect. When the water cement ratio is 0.4-0.46, the gas content is 1-3.5, and the freezing temperature is below - 5℃, the model based on the flexural tensile strength index has the best evaluation effect. The explainable parts of the two models are 99.1% and 99.2% respectively, and the fitting degree of the damage evaluation value and the measured damage value is 0.997 and 0.998 respectively. The model has a good fitting degree. The evaluation effect of the model is better than that of the existing model. The determination of the model is of great significance to the future pavement maintenance work.