Enhancing the Properties of Self-Compacting Concrete by Using Steel and Polypropylene Fibers

Ductility and strength characteristics of hardened concrete can be enhanced by using optimum percentages of steel (ST) fibers and polypropylene (PP) fibers. It moreover helps to control multi-level cracking in reinforced concrete (RC) structures. However, such addition gradually diminishes the workability. Self-compacting concrete (SCC) is capable of flowing freely due to its own weight; it fills the form completely and consolidates without any vibrational device. Hence studies have been done to modify the properties of SCC with optimal content of such fibers to achieve greater workability. European federation of national associations representing for concrete (EFNARC) and ASTM standard guidelines have been utilized to conduct all the tests on the fiber-reinforced fresh and hardened SCC concrete. These steel and polypropylene fibers were varied in SCC from 0% to 1.5% by weight of concrete under varying mix proportions. Different tests including slump flow, V-funnel, L-box, and the U-box test were performed to achieve the fluidity and filling ability for fresh SCC. Furthermore, unit weight, spilt tensile strength, compressive stress, and flexural strength of the SCC were also evaluated. The 28-day compressive strength of the SCC-I and SCC-II mixes having a fiber content of 1.5% was found to be increased by 10% and 32% than those of controlled concrete mix. The 28-day flexural strength of the SCC-I and SCC-II mixes having a fiber content of 1.5% was found to be enhanced by 16.82% and 23.9%. Hence, all the fluidity, filling ability, and strength properties of SCC with steel and polypropylene fiber mixes are discussed in detail.