ENHANCEMENT OF SOFT SOIL SUBGRADES USING SUSTAINABLE WASTE-BASED STABILIZATION MATERIALS FOR FLEXIBLE PAVEMENT APPLICATIONS

This study investigated the effectiveness of Kota Stone Mining Waste (KSMW), Lime, and Rice Husk Ash (RHA) as sustainable stabilizing materials for improving the engineering properties of soft subgrade soil for flexible pavement applications. Based on the experimental investigation, the following conclusions are drawn: 1.    The incorporation of KSMW, Lime, and RHA significantly improved the engineering characteristics of the soft subgrade soil by reducing plasticity and enhancing overall soil stability. 2.    The stabilized soil exhibited improved compaction characteristics, with an increase in Maximum Dry Density (MDD) and an optimum Optimum Moisture Content (OMC) suitable for field compaction. 3.    Significant improvements were observed in the California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS) compared with the untreated soil, indicating enhanced load-bearing capacity and strength suitable for flexible pavement subgrades. 4.    Strength development increased with curing time due to pozzolanic reactions between lime, Rice Husk Ash, and the calcium-bearing minerals present in Kota Stone Mining Waste, resulting in the formation of cementitious compounds that improved the soil structure. 5.    XRD and XRF analyses confirmed the mineralogical and chemical changes responsible for strength enhancement, supporting the laboratory observations of improved engineering performance. 6.    Regression analysis demonstrated a strong correlation between compaction characteristics and strength parameters, indicating that stabilized soil performance can be effectively predicted using statistical models. 7.    The combined utilization of KSMW, Lime, and RHA provides a sustainable and economical alternative to conventional stabilizers by reducing the consumption of natural construction materials, minimizing industrial and agricultural waste disposal, and lowering the environmental impact of pavement construction.

[1] T. G. Soosan, C. S. Jose, and A. Abraham, "Utilization of quarry dust in geotechnical applications," Journal of Materials in Civil Engineering, vol. 17, no. 3, pp. 289–296, 2005. [2] A. Sridharan, S. N. Rao, and V. Sivapullaiah, "Compaction and strength characteristics of quarry dust stabilized soils," Indian Geotechnical Journal, vol. 36, no. 2, pp. 115–126, 2006. [3] J. C. Okagbue and T. U. S. Onyeobi, "Potential of marble dust to stabilize red tropical soils for road construction," Engineering Geology, vol. 53, no. 3–4, pp. 371–380, 1999. [4] C. Eze-Uzomaka, A. Agbo, and J. Oti, "Stabilization of lateritic soil using cement and quarry dust," Electronic Journal of Geotechnical Engineering, vol. 15, pp. 1219–1230, 2010. [5] M. Ogbonnaya and A. Illobachie, "Engineering properties of granite dust stabilized clay soils," International Journal of Engineering Research, vol. 2, no. 4, pp. 245–252, 2011. [6] M. Gupta and R. K. Sharma, "Stabilization of expansive soil using marble dust and fly ash," International Journal of Civil Engineering Research, vol. 4, no. 3, pp. 281–288, 2013. [7] R. Mishra, A. Pandey, and S. Singh, "Improvement of expansive soil using granite slurry waste," International Journal of Engineering Science and Technology, vol. 6, no. 8, pp. 356–364, 2014. [8] A. Khader, M. Ahmed, and S. Rahman, "Stabilization of expansive soil using lime and granite dust," Construction and Building Materials, vol. 152, pp. 315–323, 2017. [9] I. Zorluer and S. Gucek, "Mechanical behavior of clay stabilized with granite waste and fly ash," Construction and Building Materials, vol. 145, pp. 183–192, 2017. [10] M. Salam, M. Hossain, and M. Rahman, "Effect of limestone fines on the engineering properties of subgrade soils," International Journal of Pavement Engineering, vol. 19, no. 10, pp. 917–926, 2018.