Bermuda grass ash as a sustainable cementing material in concrete for ethiopian construction industry

Abstract

The general constituent materials of concrete are a binding material, fine aggregate, coarse aggregate and water. Ordinary portland cement (OPC) is the common form of binding material used in concrete which acts as a bonding material for the fine and coarse aggregate. However as OPC is a major contributor of CO2 creating several environmental issues, researchers are now are keen to find out alternative cementing materials which can partially or fully replace OPC in concrete. This research paper presents the suitability of Bermuda Grass Ash (BGA) which is abundantly available in Ethiopia as an alternative cementing material in concrete. For this research work C-25 grade of concrete has been used. Physical and chemical properties of BGA were studied to initially identify the suitability of this material as a cementing material. Further the mechanical and durability properties of concrete with BGA as a cementing material was studied. Concrete test specimens with different percentages of BGA (0%, 5%, 10%, 15% and 20%) as a partial replacement of OPC were prepared and tested for their mechanical and durability properties at 28 days of curing. Workability test was conducted as part of the fresh properties of concrete and at hardened state, the density, compressive strength, abrasion resistance and water absorption of concrete were studied. The test results showed that, BGA when used as a partial replacement of cement upto 10%, the strength limit of concrete remains within that of C25 grade concrete (26.62 MPa). Inclusion of BGA as a cementing material helped in enhancing different durability aspects of concrete. Hence it can be concluded that optimum uses of BGA as a cementing material in concrete can be a sustainable approach for construction industry in Ethiopia.