A coupled model of chloride transport and high-temperature damage for high-strength self-compacting lightweight aggregate concrete

This study developed a novel coupled model of chloride transport and high-temperature damage of concrete. High-temperature exposure tests (20-600 °C) and subsequent chloride penetration tests for high-strength self-compacting concrete (HSSC) using two types of LWAs with various replacement ratios were conducted to reveal the coupling effect of thermal damage and chloride attack. A coupled model of chloride transport in damaged concrete was established by incorporating temperature-dependent damage variables and unsaturated chloride transport characteristics. The results demonstrate that high temperature and LWAs replacement ratio synergistically enhance chloride transport capacity. The most obvious increase of free chloride content occurred when the exposure temperature increased from 200 °C to 400 °C. Compared with FAC, the application of CCS is more effective in reducing the temperature rise at the specimen center, exhibiting superior thermal insulation and corrosion resistance. Furthermore, the proposed model can reliably reproduce the chloride penetration behavior in thermally damaged HSSC-LWAC.