A Study on Economy by Application of Agricultural Waste Materials for Improvement of Sub-grade of Flexible Pavement

Abstract

This paper presents results of an experimental investigation, carried out to study the effects of admixture like rice husk ash (RHA) on the strength properties of a locally available clayey soil with soft consistency. This soil was mixed with different proportions of RHA (3%, 6%, 9% and 12% by weight of dry soil) at corresponding optimum moisture content (OMC) and also at moisture contents 2% and 5% above optimum moisture content (OMC+2%), (OMC+5%). The cost of stabilization may be minimised by using the agricultural waste materials like RHA which also minimises the environmental hazards. The laboratory test results show marked improvement of strength of soil on addition of admixture (RHA) in terms of California Bearing Ratio (CBR). It appear from the experimental results, soaked CBR value of untreated soil is 3.50% and reaches maximum value i.e 16.80% when mixed with 9% RHA at the respective OMC. Further, an attempt has been made to observe the effect of moisture on the strength properties of the original as well as stabilized soil. The paper highlights the use of RHA for sub-grade improvement in case of low cost roads.