EF'F'ECT OF CURING DAYS ON CONCRETE MADE BY PARTIALLY REPLACED CEMENT BY FLY ASH

Abstract

Concrete is a construction material that is mostly used across the world. It is a composite material made out of water, cement, fine aggregate (sand) and coarse aggregate (stones). However, the manufacturing process of raw materials used in concrete such as cement and ag$egate causes environmental influences (emission of greenhouse gases and dust) and significantly consumes energy and natural resources. Aggregate normally accounts 70 to 80 o/o of the entire volume of concrete, while water and cement account 20 to 30 o/0. These percentages affect the mechanical properties of concrete. Replacing any of these materials by industrial waste material can have a positive impact on the environment. Hence, this project has focused on evaluating the opportunity of using one of these waste materials which is the fly ash as a partial replacement material for cement. Fly ash is generally considered as a waste material that is produced as a by-product of coal combustion process. The physical and chemical properties of fly ash are similar to cement, which allows it to be used in concrete. The primary aim of this research is to determine the feasibility of using fly ash as a replacement of cement in concrete and their effects on the mechanical properties of concrete. This Paper presents the results of an experimental investigation calried out to evaluate the mechanical properties (workability and compressive strength) of concrete mixtures in which cement was partially replaced with Fly Ash. Cement was replaced with two percentages (5Yo' lO%) of fly ash by weight. Tests were conducted for properties of fresh concrete (workability), and compressive strength was detennined at7,14 and 28 days. Test results indicate significant improvement in the strength properties of plain concrete by the inclusion of fly ash as partial replacement of cement and can be effectively used in concrete structures.