Author/Authors :
MESSAOUDENE, IBRAHIM Bordj Bou Arréridj University - Civil Engineering Department, Characterization and Valorization Laboratory of Natural Resources, Algeria , MOLEZ, LAURENT Institut national des sciences appliquées de Rennes-INSA - Mechanical and Civil Engineering Laboratory, France , JAUBERTHIE, RAOUL Institut national des sciences appliquées de Rennes-INSA - Mechanical and Civil Engineering Laboratory, France , KESSAL, OUSSAMA Bordj Bou Arréridj University - Civil Engineering Department, Algeria , SLAMA, LAHCENE Bordj Bou Arréridj University - Civil Engineering Department, Algeria
Abstract :
Many studies have permitted the analysis of the mechanical behavior of concrete subjected to high temperatures. However, no one has done any work on the effect of re-humidification of cementitious materials exposed to a real fire. This is the first study. To better simulate the effects of a real fire, a test with wood fire is developed. Different cementitious materials (hardened cement pastes, and mortar) are subject to this heating for 1hour. The results of tests indicate that: * The average resistance loss is in the order of 60% after exhibition in fire. * The re-humidification (sudden quenching in water) allowed a recovery of mass about 10% and consequently a gain of compressive strength about 40%. * Internal micro-structure analysis of cement pastes studied by XRD and the observation by a scanning electron microscope (SEM) shows that after the re-humidification, the cement rehydrates again (formation of Portlandite and CSH). Those observations explain the increase mechanical strength.
