Liquid Nano-acrylic Co-Polymer as Additives with Cement and Hydrated Lime for Stabilizing Highway Subgrade Silty Soil

This research aims to study the impact of Zycobond and Terrasil (liquid nano-acrylic co-polymer) as additives with cement and hydrated lime for stabilizing highway subgrade silty soil. Laboratory tests were conducted to identify the most suitable rehabilitation technique for subgrade silty soils with high plasticity at optimal moisture levels, and to assess the related performance characteristics (i.e., unconfined compressive strength (UCS), California bearing ratio (CBR), and permeability) for the implementation of environmentally friendly road pavement systems. Atterberg's limits, hydrometer analysis, UCS, direct shear, AASHTO, and unified classification systems were used to identify the fundamental characteristics of the reference soil. Three types of soil modifiers were considered: Portland cement (PC), hydrated lime (Ca(OH)2), and nano polymer solution. To determine the best ratio for the nano polymer solution, three different percentages of PC and Ca (OH) 2 were selected by soil weight (1%, 3%, and 5%) at OMC. 1%Ca(OH)2 and 3%PC were more suitable according to the UCS, and the Atterberg limits. The results indicated that the reference soil's maximum compressive strength (qu) improved when treated with either 3%PC or 1%Ca(OH)2 combined with the nanopolymer solution. The compressive strength increased by 67.41 percent and 28.35 percent, respectively. The permeability of the soil modified with 3% PC and 1% Ca(OH)2 using the nanopolymer solution decreased by 87.55 percent and 93.3 percent compared with the reference soil, respectively. It was found that the increase in CBR in 3% PC-modified soil treated with a nano polymer solution was 378.66 percent, whereas in 1% Ca(OH)2-modified soil treated with the same solution, it was 231.17 percent compared to the reference soil.