MODELING AND EVALUATION OF THE STRENGTH PROPERTIES OF OKE-BALE SOFT SOIL AMENDED WITH CALCIUM CHLORIDE SALT

Abstract

This research aimed to model and assess the impact of calcium chloride salt (CCS) on the Oke Bale soft soil, known as Lateritic soil, in Osogbo, Nigeria, as a potential pavement material due to high cost of conventional materials. The conducted laboratory tests included particle size distribution, Liquid limit (LL), Plastic limit (PI), and Plasticity index (PI), compaction (Maximum dry density (MDD); Optimum moisture content (OMC) with compactive efforts of British Standard Light, West Africa Standard, and British Standard heavy, and unsoaked California bearing ratio (CBR) on both Oke bale soft soil and modified soil. The soft soil underwent stabilization with varying concentrations of CCS at 0, 4, 8, 12, and 16%. The results were analyzed using regression analysis and Analysis of Variance (ANOVA). The findings indicated advancement in the gradation of lateritic soil as the percentage of CCS salt increased. Additionally, the PI lessened from the value of 14.68% in the regular lateritic soil to the value of 11.49% at 12% CCS content, afterward amplified to the value of 15.6% at 16% CCS content. Simultaneously, the LL of the natural lateritic soil decreased from 60.05% to 35.55% at 16% CCS content. The MDD of original lateritic soil for BSL, WAS, and BSH decreased from 1.63 to 1.45 Mg/dm³, 1.66 to 1.48 Mg/dm³, and 1.69 to 1.52 Mg/dm³ at 4% CCS content, subsequently increasing up to 16% CCS, respectively. Although the OMC amplified from 19.47% to 24.0%, 18.22% to 22.73%, and 17.44% to 21.85% at 4%, it later increased up to 16% CCS, respectively. At 8% CCS content, the CBR value improved from 13.22% to 24.65%, 14.44% to 26.28%, and 15.68% to 28.62% for BSL, WAS, and BSH compactive effort, respectively. Regression analysis indicated that grading properties, MDD, LL, PF, and PI influenced strength qualities of Oke-bale lateritic soil amended with CCS, with positive coefficient values. Furthermore, regression analysis suggested a solid bond between the measured and predicted values of CCS-LS. However, statistical significance was shown in the lateritic-CCS mixed analyses of variance during the duration of the test. Based on the outcome of CBR test, 8% CCS-lateritic soil mixture could be effectively utilized to enhance low-traffic roads.