ENHANCING THE CONSISTENCY LIMIT AND MECHANICAL PROPERTIES OF A SOIL - CASHEW LEAF ASH - RICE HUSK ASH BLEND FOR SUSTAINABLE CONSTRUCTION.

ABSTRACT This project looks at the properties of expansive soils and how mixing them with cashew leaf ash (CLA) and rice husk ash (RHA) can improve their suitability for construction. Expansive soils expand and shrink with changes in moisture, which causes problems in building projects. First, the study examines the soil and its limitations for construction. Then, it explores how adding CLA and RHA can improve the soil's consistency and strength. Using regression analysis, the study shows how different amounts of CLA and RHA affect important soil properties like the California Bearing Ratio (CBR), Maximum dry density (MDD), and Optimum moisture content (OMC). The results show that these natural additives can significantly improve the soil’s properties, making it more suitable for sustainable construction. From the results, it was revealed that the highest CBR value was 55.2% at 20% replacement of CLA and RHS, and a corresponding value of 16.25% and 1.87g/cm3 for OMC and MDD respectively. The findings from this detailed analysis demonstrated the effectiveness of the regression model, with high coefficients of determination (R-squared) values: 85.09% for CBR (California Bearing Ratio), 86.37% for MDD (Maximum Dry Density), and 89.69% for OMC (Optimum Moisture Content). These high R-squared values indicate that the model effectively explains the variation within the data. To evaluate the statistical significance of the dataset used in the model, an analysis of variance was performed at a 95% confidence level. The resulting p-values were 0.006 for CBR, 0.002 for MDD, and 0.001 for OMC, indicating a very high level of statistical significance.