Experimental Study of Improving the Properties of Lime-Stabilized Structural Lateritic Soil for Highway Structural Works using Groundnut Shell Ash

Abstract

This research considered the viability of groundnut shell ash (GSA) on lime-stabilized lateritic soil for highway structural works. Three samples of lateritic soil, named samples A, B, and C, were gathered from Idita-Mokuro, NTA-Mokuro, and ETF burrow pits, respectively, in Ile-Ife, Osun State, Nigeria. Preliminary tests were completed on the samples in their natural states and when stabilized with optimum lime. Engineering properties were performed while 2, 4, and 6 % GSA contents were added to the soil samples at optimum lime. The Atterberg limit tests showed a significant reduction in the plasticity index for samples A and C when stabilized with lime. Compaction test showed a decrease in the maximum dry density from 1,685 to 1,590 kg/m3 for sample A, 1,599 to 1,512 kg/m3 for sample B, and 1,396 to 1,270 kg/m3 for sample C on stabilizing with lime; the introduction of GSA to stabilized lime soil diminished the maximum dry density for all the soil samples, with sample A reduced to 1,435 and 1,385 kg/m3 at 2 and 4 GSA contents, respectively. The addition of GSA improved the engineering properties of lime-stabilized soils as the unsoaked CBR esteems expanded for all soil samples. At an optimum lime dosage, the addition of 2 % GSA expanded the triaxial shear strength from 60.43 to 188.36 kN/m2 for sample A and, at 4 % GSA content, both soil samples B and C increased from 19.19 to 201.48 kN/m2 and 30.62 to 111.65 kN/m2, respectively. Conclusively, GSA improved the toughness and strength of lime-stabilized lateritic soil for highway structural works.