Flexural properties after exposure to elevated temperatures of a ground granulated blast furnace slag concrete incorporating steel fibers and polypropylene fibers

摘要

Experiments were carried out to investigate the flexural properties of fiber-reinforced ground granulated blast furnace slag (GGBFS) concrete after exposure to high temperatures. On the basis of experimental observation, the effect of GGBFS content, the steel fiber dosage, the polypropylene (PP) fiber dosage, and the strength grade on the residual strength of concrete after exposure to elevated temperatures were systematically examined. Test data indicate that exposure to high temperatures causes deterioration in the flexural strength of concrete; inclusion of GGBFS, PP fibers, and steel fibers, all effectively improve the residual flexural strength of concrete after fire. The optimum amounts of GGBFS, PP fibers, and steel fibers are identified respectively for better fire resistance of concrete. The strength losses of concretes characterized by different strength grades are very close to one another. Equations are proposed to predict the residual flexural strength of concrete incorporating GGBFS, PP fibers, and steel fibers after being heated to temperatures up to 800℃.