A coupled damage model for RC structures: Proposal for a frost deterioration model and enhancement of mixed tension domain

•An enhanced coupled mechanical–environmental damage model was developed.•The effects of freeze–thaw cycles on concrete behavior were included.•A more comprehensive representation of the mixed tension domain of concrete was proposed.•Experimental and numerical results were compared. The coupled chemical–mechanical damage model developed by some of the authors was enhanced concerning both mechanical and environmental aspects. A more comprehensive representation of the mixed-tension domain was developed, together with the proposal of an innovative formulation to account for frost attack. The mechanical enhancement was validated by means of comparison with different experimental tests. Then the parameters of the proposed environmental model were calibrated by using a limited number of tests on concrete specimens under freeze–thaw-cycles. Afterwards it was used as predictive tool for simulating different series of tests and to evaluate the load-carrying capacity of a frost-damaged beam.