Abstract: Most areas in the west are dry and rainless, the temperature difference between day and night is obvious. When the thermal insulation wall panel is in a harsh environment, local stress concentration will occur, which will lead to cracks and shorten its service life. The wet-dry cycle accelerated test was designed, the mechanical properties were tested, the internal structure evolution was observed, and the relative mass and relative dynamic elastic modulus was measured for radar analysis and numerical regression. Finally, based on Wiener model, the reliability of samples was predicted, and the performance degradation law of cement-based composite cored wallboard under wet-dry cycle accelerated was comprehensively analyzed. The resultsshowed thatthe strength increases with the continuous acceleration test of wet-dry cycle, and the compressive strength reaches 42.5 MPa and the flexural strength reaches 9.5 MPa. The internal reaction of microstructure produces more precipitated CaCO₃, and gradually develops from denser to looser. The evaluation parameters initial increase from 1 and then decrease , but the overall change state is a decreasing trend, and the mass loss rate has a low sensitivity and a high correlation degree relative to the dynamic modulus. Through regression model analysis, the evaluation index meets the changing law of polynomial function, and the working life mass loss and dynamic elastic modulus by reliability analysis is4 500 d and 3 500 d, respectively.

Key words: cement-based composite cored wallboard, mechanical properties, microstructure