Optimum fly ash content to improve the geotechnical properties of expansive soil

Abstract

Expansive soils pose a serious challenge to civil engineering constructions due to their ability to swell and shrink upon wetting and drying. This phenomenon usually leads to damage of the structure when the soil is not treated properly. Moreover, the disposal and utilization of fly ash (FA) in both economical and eco-friendly ways has received high attention in the world. Thus, this study focuses on the improvement of the geotechnical properties of expansive soils stabilized with varying percentages of fly ash as an admixture. In the present study, low calcium fly ash in different proportions by weight (0%, 10%, 20%, 30%, and 40%) was added to a moderately expansive soil collected from Doharramafi Village, India. Laboratory tests performed on the prepared mixtures included the determination of moisture-density relationships, California bearing ratio (CBR), and shear strength parameters. Test results show that moisture-density relationships, CBR values, and shear strength parameters of fly ash-treated soil are significantly modified and improved compared to control specimens. Furthermore, based on all laboratory tests, 30% fly ash content is observed to be the optimum fly ash quantity required to improve the geotechnical properties of soil stabilized with fly ash.