Étude des performances et de la durabilité des bétons fibrés.

Abstract

Research on fiber-reinforced concrete has developed considerably in recent years. They are increasingly interested in reinforcing structural concrete with untreated vegetal fiber. The incorporation of fibers into concrete is intended to improve the mechanical performance of concrete such as tensile strength and cracking limitation. The use of natural fibers could be an alternative with lower environmental and economic impact compared to synthetic fibers made from petroleum derivatives. The objective of our research is the study of the behavior of fiber-reinforced concrete, more particularly with vegetal fiber, in the face of temperature rise and their durability in the face of external sulphate attack compared to synthetic fibers-reinforced concrete. Two different fiber lengths were studied (20 and 30 mm). Five types of concrete were made, two types of concrete reinforced with 1% by volume of alfa fibers with the two lengths (AC-20 and AC-30), two concrete reinforced with 0.22 % by volume of polypropylene fibers with the two lengths (PC-20 and PC-30) and ordinary concrete taken as control concrete (OC). The concrete samples produced were exposed to heating / cooling cycles from room temperature to a set temperature of 180, 380 and 600 °C, other samples (7x7x7 cm) were immersed in a solution dosed at 5% Na2 SO4 for 12 months. The results showed that alfa fibers can replace polypropylene fibers in the reinforcement of concrete by improving their behavior in the face of temperature rise and their durability in the face of external sulphate attack and having a better impact on the environment.