Experimental Investigation on Mechanical Properties of M25 Grdae Concrete Containing DCA, Silica Fume and Steel Fiber

Abstract

This research included a collecting a Demolished Concrete from the demolition of building at site, Crushing Demolished Concrete waste and is separated with different sizes using sieve analysis. The purpose of this research is to investigate the mechanical properties of Demolished Concrete Aggregate (DCA) concrete. Five DCA concrete ratios are prepared experimentally by substituting, 0%, 25%, 50%, 75% and 100% of the gravel weight with DCA. While, the 10% of cement is substituted by silica fume (Si). Steel fibers acts as a bridge to retard their cracks propagation, and improve several characteristics and properties of the concrete. Fibers are known to significantly affect the workability of concrete. The aspect ratio and variable in this study were percentage of volume fraction (0, 0.5, 1.0 and 1.5) of steel fibers. Compressive strength, splitting tensile strength and flexural strength of the concrete were determined for the hardened properties. Their main purpose is to increase the energy absorption capacity and toughness of the material. But also, the increase in tensile and flexural strength is often the primary objective. A marginal improvement in the ultimate strength was observed. Adding steel fibers (SF) (0.5 %, 1.0 % and 1.5 %). The water absorption of recycled aggregates is higher than the natural aggregates. The range may vary based on the type of aggregates and in this case, it is 9% higher. This is also because of the attached mortar present on the aggregate surface which has a tendency to absorb more water. Concretemix DCA 50 % Si 10% SF 1% shows good strength at 7days (2.89N/mm2) and Mix DCA 50 % SF 1.5% shows good strength at 28 days (7.91 N/mm2).