Etude du Comportement du béton soumis à haute température : Influence du type de béton et de la nature des constituants

Abstract

ABSTRACT : Concrete damage by fire which affects more buildings have raised the question of the behavior of concrete (ordinary or high performance) versus the fire. Theoretical and experimental studies have allowed having an explanation of the phenomena observed in the behavior of heated concrete and clarify key parameters influencing fire behavior of concrete. The main objective of this research is to supplement, by an experimental study, existing knowledge on the behavior of concrete subjected to high temperatures by focusing on the behavior of aggregates. This study is built in three parts: the study of the behavior of aggregates (silica sand, limestone sand, limestone aggregates and crushed brick aggregates) subjected to high temperature, the study of the behavior of concretes with aggregates previously tested and finally the observations at different scales of degradations of these concretes. Three concrete families were studied: ordinary aggregates concrete (silica sand and limestone aggregates), concrete with calcareous sand (calcareous sand and limestone aggregate) concrete with crushed brick aggregates (silica sand, 70% limestone aggregates and 30% crushed brick aggregates). For each concrete family, three W/C ratios are used: 0.60, 0.42 and 0.27. The concretes are subjected to heating-cooling cycles to 150°C, 250°C, 400°C, 600°C and 900°C. The residual physical and mechanical properties of different concretes were analyzed. The analysis of the test results used to characterize the various physical and mechanical properties of concretes at high temperatures. The results show that the crushed brick aggregates and concrete made with these aggregates show a better behavior when submitted to high temperature.