Prediction of spalling in fibre-reinforced high strength concrete at elevated temperatures

This experimental study investigates two spalling test methods, for small scale specimens made of fibre-reinforced high strength concrete exposed to elevated temperatures, namely a blowtorch test and a furnace test. The study also aims at developing a relationship between relative maximum pore pressure and spalling, in order to determine a threshold relative maximum pressure for predicting spalling in heated concrete. The test results showed that the blowtorch test was a more effective and economical test method for carrying out spalling tests in small, unloaded and unrestrained specimens. Since such small specimens almost always do not spall during furnace tests, a blowtorch spalling test can help to provide relevant and useful data for mitigation of spalling in real scale structural elements. Also, with a blowtorch spalling test, a clear relationship between relative maximum pore pressures and spalling in heated concrete was observed, and a threshold relative maximum pore pressure above which spalling is likely to occur was suggested.