EFFECT OF RICE HUSK ASH WITH COCONUT HUSK ASH ON GEOTECHNICAL PROPERTIES OF LATERITIC SOIL

Abstract

This research is aimed at assessing the effect of rice husk ash with coconut husk ash on geotechnical properties of lateritic soil at Makole area, Warawa Local government, Kano state of Nigeria using 0, 2.5%, 5.0% and 7.5% of the combine husk ash by mass of soil sample at different combinations of RHA and CHA in percentage. In order to achieve our research goal, the following laboratory soil tests were carried out on the lateritic soil sample: particle size distribution analysis, Atterberg limit test, compaction test, and California Bearing Ratio in accordance with British Standard 1377 (1990). Chemical composition analysis of the rice husk ash and coconut husk ash was done as well.  Chemical analysis of the rice husk ash and coconut husk ash is shown in Table 2 and table 3 respectively. The results obtained show that the increase in combine husk ash content increased the OMC but decreased the MDD. It was also discovered that increase in combine husk ash content, increased plasticity and increased plastic index as well as the strength of the soil. 70%:30% of combine RHA and CHA content was also observed to be the optimum content. The result indicates that combination of rice husk ash and coconut husk ash is suitable for improving the California bearing ratio because this parameter increases with a combination of 70%:30% RHA:CHA combination. Addition of coconut husk ash also increases the plastic limit and increases the plasticity index. Therefore, this study shows that coconut husk ash can be effectively used to improve lateritic soils with low CBR values but not suitable for improving soils with high liquid limit.

KEYWORDS: Rice husk ash, coconut husk ash, lateritic soil, California bearing ratio