Stabilization of Expansive Soils with Agricultural Waste

The United States’ top provider of long-grain rice is Arkansas. The burning of the outer shell of paddy under controlled circumstances generates rice husk. A significant portion of the ash created during the rice-milling process is silicate, which is a pozzolanic substance that may enhance the strength of poor soils. By examining two local subgrade soils from Arkansas, the primary goal of this study is to determine the optimal amounts of hydrated lime, Rice Husk Ash (RHA), and RHA + lime. Various tests, including the Atterberg Limits, Modified Proctor, Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR), pH, and Free Swell (FS), were performed on the treated soils. The findings of the tests indicate that the maximum dry density and plasticity of the soil are decreased by both RHA and lime. On the other hand, adding either RHA or lime improved the treated soils’ strength characteristics. According to the FS results, the soil’s swelling was decreased by both RHA and lime. But it was shown that lime was more successful than RHA in lowering the FS of soils. RHA has no discernible impact on soil pH; however, lime causes a significant rise in pH. It was found that the best dosages for treating both soils were 6% RHA and 3% lime. The swelling potential may be decreased, and the strength properties could be enhanced by the combination of RHA and lime. Based on laboratory test findings, it is recommended to stabilize poor subgrade soils using 4% RHA + 1% lime.