Properties of high-strength concrete containing polypropylene and glass fibers

Abstract

High strength concrete (HSC) posses more problems, since it has less ductility in comparison with normal strength concrete (NSC). To overcome this problem was reinforced with fibers and hybrid fibers. The effects of fibers and hybrid fibers upon the properties of high-strength concrete mixtures containing superplasticizing admixtures have been investigated. The properties of fibrous high-strength concrete and high-strength concrete are compared. Results showed that decrease in workability of all concrete mixtures containing polypropylene, glass and hybrid fibers compared with control mix. It was found that the addition polypropylene fibers increase the suitable w/c ratio to save the workability from 0.24 to 0.26, 0.27 and 0.29 at 0.5, 1.0 and 1.5 volume fraction respectively. While the w/c ratio increased to 0.35 when the 0.4% glass fiber was added. HSC with 1.5% polypropylene fibers showed superior splitting and flexural strengths over the other concrete without or with fibers, compared with HSC without fibers the increasing were 30.76% and 25.61% respectively. At 28-day age, fibrous high-strength concrete showed higher compressive, splitting and flexural strengths than the high-strength concrete, depending upon the types and volume fraction of fibers. The results obtained demonstrate that the addition of the hybrid fibers to the high strength concrete showed that the ratio of (0.7% polypropylene+0.12% glass fibers) at volume fraction 0.82% gives better fresh and hardened properties than the ratio (0.3% polypropylene+0.28% glass fibers) at volume fraction 0.58%. The maximum increase in compressive strength, splitting strength and flexural strength of high strength concrete contains (0.7% polypropylene+0.12% glass fibers) were 9.57%, 15.38% and 14.04% respectively.