Study of vapor pressure of high performance concrete and self-compacting concrete slabs subjected to standard fire conditions

In this study a novel fire test system including in situ monitoring of internal pore vapor pressure and temperature history inside the concrete is first introduced. The fire test system was used to measure high performance concrete slabs and self-compacting concrete slabs at different layer depths from the fire front, i.e., 10 mm, 20 mm and 30 mm when the slabs were subjected to the standard ISO 834 fire conditions. Microstructural investigation was performed on parallel samples exposed to small furnace. The total porosity and pore size distribution were measured by mercury intrusion porosimetry. The vapor pressure build up is investigated, as wall as the correlation between the vapor pressure distribution, the temperature history, the initial moisture content, the porosity/pore size distribution. Some possibilities of preventing concrete spalling are discussed.