Green Concrete for Green Building

Abstract

Concrete mixture can be made clean, green and economic. This research intends to find out the effect on the strength and economy of concrete as a result of substituting cement and sand with fly ash and bottom ash respectively. Fly-ash and bottom ash are waste of thermal power plant and they are hazardous to environment but they can be utilized in concrete mixture for construction. Fly ash's role in concrete is as a substitute for cement because of its pozzolanic properties thus reducing the cost of concrete. Bottom ash has specific gravity less than sand so, its replacement results in reduction of concrete's weight.  In this study, detailed experimental investigation is done to study the effect of partial replacement of cement with fly ash and fine aggregate with bottom ash for the mix design of M20 grade concrete. Components were replaced by 5% weights of cement and fine aggregate and continued by incrementing one percentage point till 30%. Destructive test were carried out on hardened concrete cubes. The samples were cured for 7days, 14days and 28 days by ponding method and tested by universal testing machine. The replacement of these components in concrete has improved the workability of concrete. The strength of the concrete cubes also increased up to a certain percentage replacement and then decreased gradually. The research model may be replicated in construction industries to save cost, reduce concrete weight and make concrete green by saving natural resources.