Effet des hautes températures sur le comportement physique et mécanique des mortiers à base de la fumée de silice et fibre polypropylène

Abstract

Mortar is a cementitious material that is often used in situations where it can be exposed to high temperatures (eg. case of fire). So, the present experimental study aims to study the physical and mechanical behaviors of an ordinary mortar exposed to high temperatures up to 600 ° C. In this study, the major interest is given to the influence of silica fume, added with different dosages to the mortars tested by substituting a quantity of cement, on the behavior of the mortar at high temperatures. Great interest is also given in this research work to the incorporation of polypropylene fibers in the mortar. For this, five formulations of mortars were tested with the same water / binder ratio and a fixed amount of polypropylene fibers, but based on different dosages of silica fume (0, 5, 8, and 12%). The mortars studied were subjected to heating-cooling cycles at maximum temperatures of 150, 300, 450 and 600 ° C. Tests were therefore carried out on the various samples of the mortar in order to determine the evolution of the mechanical resistance. (in traction and in compression), the porosity accessible to water and the sorptivity of the material as a function of the temperature. The results show the effects of high temperatures on the physical and mechanical behaviors of the mortars studied as well as the significant influence of silica fume and polypropylene fibers on these behaviors of the material in the face of high temperatures.