“Effect of Polypropylene Fibers on Producing Sustainable Accelerated Hardened Cementitious Materials”

Abstract

The aim of this research is to produce environmental friendly cementitious materials using polypropylene fibers as recyclable reinforcement materials and silica fume (side-product in manufacturing of ferro-silicon alloys and silicon metal) material. The manufacturing process includes using accelerating curing with carbon dioxide for the fresh cementitious mixtures to decrease setting time and improve hardening, particularly in precast concrete plants.Mix proportions used in this research were cement: silica fume: Sand (1: 0.75: 1.3) and 0.5 w/c ratio. Also, four percentages of polypropylene fibers are used (0, 0.3, 0.9, and 1.5%) by weight of cement. All specimens are exposed to 100% of carbon dioxide gas concentration for 2 hours. Compressive, flexural, and direct tensile strengths have been tested at 7 and 28 days. The results show a significant improvement of flexural strength and direct tension for specimens. The increasing percentages of flexural strength and direct tension with (1.5% polypropylene) compared with control mixture at age 28 days were about (+ 28%) and (+ 117%) respectively.