ABSTRACT

Rice husk ash and saw dust ash are good materials that can supplement cement to some extent but the percentage of saw dust ash and rice husk ash should not be more than 15% of cement. For a given mix, the water requirement increase as the rice husk ash and saw dust ash content increases. The increased water demand is as a result of increased carbon content. This is because the carbon content of ordinary Portland cement is very small compared to that in Rice husk ash and Saw dust ash. So as ash is introduced into the mix, the carbon content increases and the water requirement also increases. The setting time of concrete with saw dust ash and rice husk ash increases as the ash content increases: The compressive strength of the concrete cubes for all mix increases with age at curing and decreases as the rice husk ash and saw dust ash content increases. This addition of rice husk ash and saw dust as is permitted for lightweight structure. All materials used for the practical are local materials and they are readily available and they can also reduce the cost of producing concrete when implemented. There has been no issue of hazardous emission generated from this material when used for construction. The mode of disposing rice husk ash and sawdust has been by open air burning which has harmful effect on the people and environment at large but with its implementation in lightweight structure, it will help in providing clean and safe environment.