Development of bricks with rice husks as filler material.

Abstract

Clay has been used as main material in fabrication of bricks however the use of waste material in brick manufacturing has been introduced for conservation of dwindling clay resources, as well as preventing environmental and ecological damages caused by quarrying and depletion of raw materials. The main objective presents the effect of incorporation of rice husk (RH) on the physical and mechanical properties of fired clay bricks. The replacement of RH with clay is as 0%, 1.3%, 2.6%, 5.3% and 10.5% by weight. The mechanical strength was improved at 800 due to sintering mechanism. Physical properties were carried out with the determination by water absorption, density, while compressive strength of clay bricks was tested. It was found the use of RH addition affected on lower bulk density of bricks. It was observed their porosity ratios up to 30% with increasing of RH addition up to 10.5wt% with 10.5% RH fired at 800. However, the compressive strength of clay brick is (490N/〖cm〗^2) with 1.3% addition after fired at 800. Conclusively, the results revealed the RH could be possibly regarded as a potential addition to raw materials used in manufacturing of lightweight fired clay bricks. Also, in this study, rice husk ash has been utilized for preparation of bricks in partial replacement of clay. The specimens were cast with different replacement levels of clay varying as 0%, 1.3%, 2.6%, 5.3% and 10.5% by weight with rice husk ash. The specimens were tested for water absorption and compressive strength. According to Ugandan standard. Experimental shows that excessive addition of rice husk ash has higher water absorption and low compressive strength as rice husk ash percentage increases rice husk ash characteristics predominate. The bonding between the clay particle and rice husk ash particles is weak. By addition of 1.3% of rice husks ash by weight is the best brick properties which is 5.75 MPa of compressive strength and 12.5% water absorption. The water absorption of RHA brick developed did not exceed 20% hence promoted to be partial replacement of clay.