Properties of Self-Compacting Concrete Containing Waste Tires Rubber as Aggregates and Filler Additives

The issue of waste accumulation exists around the world, particularly in the densely populated regions. These waste materials not biodegradable in nature, so it is left as stocks or dumped illegally. The burning millions of tons of waste tires creates great risk. To prevent the hazardous effect of produced chemical gases (CO2) through combustion processes, many research attempts to use huge amounts of rubber waste in concrete mixes. In this paper, properties that are both fresh and hardened of self-consolidating concrete with different sizes of waste tires rubber and micro steel fibers were investigated. The various sizes of waste tires rubber were utilized in place of coarse and fine aggregates, limestone (Al-Gubra) and silica fume after obtaining a rubber size close to the size of each material that has been replaced. Coarse and fine aggregates were replaced with chip and crumb rubbers (20% and 10% by weight). Al-Gubra and silica fume were replaced with ground and finely ground rubbers (50%, 25%, and 12% by weight). The experimental results showed that the fresh properties of self-consolidating concrete had been adversely affected by incorporating micro steel fibers and scrap tires rubber, but remained within the European Federation of National Trade Association Representing Concrete (EFNARC). The results of tests also showed that the mechanical properties decrease when used rubbers as aggregates. However, the results demonstrated that the compressive as well as splitting tensile strength of specimens increased by replacing lime stone dust and silica fume with rubbers. The increases were (12.2-28.0) % and (11.6-41.9) % for compressive strength and splitting tensile strength, respectively.