In the present experimental research, concretes of five strength grades were used to investigate the behavior of high performance silica fume concrete with different moisture contents subjected to the ISO standard fire. The spalling test results obtained from the 100 mm cube specimens revealed that moisture content and strength grade are the two main factors governing the explosive thermal spalling behavior of concrete. Moisture content has a dominant influence on the occurrence of spalling. The dependence of spalling on moisture content and strength grade confirmed the vapor pressure build up mechanism of spalling. The rebound hammer tests carried out on the post fire concrete slabs showed that the spatial distribution of residual mechanical property inside the slabs correlated with the temperature field. Conventional methods generally adopted are too simple for describing the residual mechanical properties of concrete subjected to fire. A new method is needed which should take into consideration both chemical and physical changes inside concrete caused by the temperature field.
