Green Concrete Using Fly Ash and Silica Fume

Abstract

Recycled coarse aggregate can also be used by partially replacing natural concrete aggregates, so that construction and demolition waste can be further used for aggregates in new construction. Recycled coarse aggregate includes brick, tile aggregates, crushed stone aggregates, glass aggregates, and demolished aggregates. In this paper, different recycled aggregates are used by 40 and 60% replacement with natural aggregates of size 20 mm. Granite stone, brickstone, concrete debris are used as Recycled Coarse Aggregates in this experimental work. Ordinary Portland Cement is replaced by 30–40% with fly ash and 10–20% replacements of silica fume are used, respectively. Finally slump tests and compression tests are conducted on the concrete cubes after 28 and 56 days to compare the results. Test results show that under the equivalent mix proportions, the workability decreases with an increment in the recycled coarse aggregate as replacement percentages. The concrete having 40% crushed granite aggregate gives optimum compressive strength of the cubes. Test results show that if any major cause happens in the society and the persons shifted to other places so the structure which is using this type of material can be used for economic feasibility.
Keywords: Green concrete, Brick stone, concrete debris, Fly ash, Silica fume, Workability, Compressive strength