Method for predicting chloride ion concentration distribution in RAC of different ages and water cement ratios

The invention provides a method for predicting chloride ion concentration distribution in RAC of different ages and water cement ratios, which comprises the following steps: after recycled coarse aggregate concrete test pieces of different water cement ratios are eroded by chlorine salt, measuring concentration distribution data of Cl in the test pieces of different ages along the erosion depth; based on the Fick's second law, fitting concentration distribution data of the Cl along the erosion depth to obtain the surface Cl concentration and the Cl diffusion coefficient of the test piece; establishing a time-varying model of the Cl concentration on the surface of the test piece and a time-varying model of the Cl diffusion coefficient; introducing an influence coefficient k, and establishing a Cl-diffusion coefficient time-varying model considering the influence of the water-cement ratio; and establishing a model for calculating the concentration distribution of Cl in the recycled c