Study on the high-temperature static and dynamic constitutive model of silicon carbide-modified concrete.

Based on experimental investigations of concrete subjected to silicon carbide (SIC) modification, high-temperature exposure, and high-strain-rate loading, this study introduces the concept of a concrete damage factor. A probabilistic damage constitutive model for silicon carbide-modified concrete under elevated temperatures was developed, formulated according to the Weibull distribution within the framework of damage probability distribution theory. The study first examines the modification mechanism of silicon carbide under coupled high-temperature and high-strain-rate damage conditions. Seven statistical parameters were identified to characterize the individual and coupled influences of silicon carbide content, temperature, and strain rate. Subsequently, a general constitutive model for concrete was formulated. Following this foundation, modified constitutive relations were systematically established. The Type I modified models account for the individual effects of each factor. The Type II modified models address the coupled effects of factor pairs, including specifically the high-temperature constitutive model and the dynamic constitutive model for silicon carbide-modified concrete. Finally, the Type III modified model was developed, incorporating the simultaneous coupling of all three factors-representing the high-temperature dynamic constitutive model for silicon carbide-modified concrete.