Study on mechanism of thermal spalling in concrete exposed to elevated temperatures

This paper presents a review of explosive spalling of concrete at elevated temperatures. The affecting factors, mechanisms and current theoretical and experimental studies are summarized. Using a numerical model proposed by the authors, numerical simulations were performed to investigate the effects of the thermally cracking process considering the effects of heterogeneity of the material properties on the spalling in concrete exposed to a transient thermal load. The investigations showed that the thermal cracking is the key factor causing the corner and surface spalling, and suggested that a coupling of thermal cracking and pore pressure is the main cause of explosive spalling and uncertainty of explosive spalling. The explosive spalling induced by elevated temperatures is a complex nonlinear problem, which can be understood only through establishing a methodology using behavioral aspects for both material science and mechanics.