Abstract:
In producing cement, all the ingredients but gypsum is sourced locally. To conserve funds used in the importation of gypsum and to proffer solution to the environmental degradation posed by the dumping of rice husk in the country, this study has looked into the possibility of using locally available materials in the development of cement. In producing the cementing materials from locally available raw materials for use in building construction industry, several mixes of Pozzolana samples were prepared. Sample B comprises of Rice husk ash, fired clay and lime; Sample C comprises of Coal ash, fired clay and lime; Sample D, comprises of Rice husk ash, fired clay, Coal ash and lime; Sample E comprises of Rice husk ash, fired clay, lime and 10% ordinary Portland cement. Sample A (Ordinary Portland Cement) served as the control sample. The samples were then subjected to physical and mechanical tests. The results of the Pozzolona Samples were compared with those of sample A (Control sample/ Ordinary Portland Cement). Samples B and E exhibited fineness closely related to sample A, which is an indication of increased rate of hydration. The result also showed; sample A with a shrinkage value of 0.69% has higher constancy volume than pozzolona samples B, C, D and E which have shrinkage values of 3.45%, 3.45%, 3.45% and 2.76% respectively. The reduction in the shrinkage value of pozzolona sample E could be attributed to the 10% addiction of portland cement. , " The compressive strength of samples S, C, D and E were found to be 13.70N/mm2, 18.00 N/mm2, 19.75 N/mm2 and 18.50 N/mm2 respectively. These were lower than that of the control Sample A which was 20.25 N/mm2. This shows that pozzolona exhibited lower strength than concrete made with Ordinary Portland Cement. However, they are higher than those obtained from sawdust concrete (Ndububa and Ndububa, 1998) and palm fruit fibre mortar (Ndububa et ai, 2001). The study showed that local raw materials such as rice husk, fly ash and burnt clay can serve as alternative to cement. The study further showed that pozzolona can be adopted for simple construction work such as roofing sheets, tiles, partitions and ceiling boards.
