Modification of Highway Sub-Grade Black Cotton Soil by using Nano Chemical: Terrasil Mixed with Fly-Ash and Rice Husk Ash
Authors: Bhat Amir Rashid , Rihal Preet Singh 
Published: March 2023

Abstract: As the population grows daily, the amount of excellent, solid ground available for development decreases, necessitating the use of weaker or softer soil for the construction of buildings and other civil engineering projects. The building of structures built on the problematic broad black cotton soil is fraught with difficulties. It has poor geotechnical subgrade features, including swelling and imperviousness. In this study, an attempt is made to improve the different geotechnical characteristics of black cotton soil by mixing it with waste products like river sand, fly ash, and marble dust. These properties include index properties, swelling characteristics, consolidation characteristics, hydraulic conductivity characteristics, and strength characteristics. Due to the best possible use of these waste materials in the enhancement of various aspects of black cotton soil, these techniques therefore minimised the impact of waste materials on the environment. There are many different types of soil stabilisation, but typically, mechanical, and chemical stabilisation procedures are used to accomplish traditional soil stability. Stabilizers are the additives that are used to stabilise substances. For stabilisation, a variety of stabilisers are utilised, including fly ash, bitumen, rice husk, lime, cement, and other chemicals. When dry, black cotton soils are extremely hard; yet, when wet, they entirely lose their strength. Widespread issues with expansive soils provide a number of difficulties for civil engineers. Numerous techniques are used to enhance the expanding soils' engineering properties. The study's findings are summarised as follows. By raising the percentage of Terrasil and maintaining the values of rice husk ash and fly ash, which are 10% and 20% respectively, unchanged, the liquid limit percentage lowers by 0% to 0.08% and grows. When Terrasil is changed while leaving the values of rice husk ash and fly ash, which are 10% and 20% respectively, unchanged, the plastic limit percentage falls from 0% to 0.10 percent. When rice husk ash and fly ash are kept at their constant values of 10% and 20%, respectively, the plasticity percentage drops from 0% to 0.04% and then rises to a high of 0.06% at 30.07. The maximum value is reached before the optimal moisture content (OMC) first increases, then declines. achieved after 0.10% addition of Terrasil while maintaining the 10% and 20% values for rice husk ash and fly ash, respectively, and were equivalent to 27.64%. The compressive strength first increases and then decreases, the maximum value obtained was at 0.06% addition of Terrasil keeping constant value of rice husk ash and fly ash, i.e., 10% and 20% respectively, and were equal to 1.69 gm/cm2. The maximum dry density (MDD percentage) first increases up to 0.06% of Terrasil and then decreases.. The greatest value achieved was at 0.06% addition of Terrasil retaining constant value of rice husk ash and fly ash, i.e., 10% and 20% respectively, and were equal to 0.861kg/cm2. The shear strength initially increases and subsequently drops. As Terrasil's percentage rises while the amounts of fly ash and rice husk ash remain constant at 10% and 20%, respectively, the permeability commonly drops.