STABILIZATION OF WEAK SUBGRADE SOIL USING WASTE CERAMIC TILE AND TIRE PIECES: ACASE STUDY IN JIMMA TOWN

Abstract

Weak subgrade soils have the tendency to behave volume change during wetting and drying scenario. This behavior of the soil cause large uplift pressure, differential settlement, and upheaval of structures built on them. These problematic soils when encountered as sub grade material should be avoided or treated properly. The aim of this study is stabilization of weak subgrade soil using waste ceramic tile and tire pieces. For this study four sub grade soils were collected from Jimma Town of Ifa bula I, Ifa bula II, M/qoci and B/kito Kebele. Laboratory tests were conducted to determine moisture content, specific gravity, and grain size analysis, Atterberg limits, proctor test, free swell test, California Bearing Ratio and CBR swell tests.The research design followed the experimental and qualitative type of study. Laboratory tests were conducted based on the AASHTO and ASTM laboratory test standards. The results show that the sub grade soils are A-7-5 according to AASHTO soil classification system and CH, MH according to USCS. Ifa bula I kebele soil sample has plastic index 53.7 %, free swell index 109.09 %, linear shrinkage 16.07%, and UCS 15.52(kpa). Similarly Ifa bula II kebele soil sample has plastic index 29.5 %, free swell index 38.48%, linear shrinkage 15 %, and UCS 146.44(kpa), M/Qoci kebele soil sample has plastic index 44.5%, free swell index 88.18, linear shrinkage 13.93%, and UCS 42.87(kpa). Finally B/Kito kebele soil sample has plastic index 38 %, free swell index 95%, linear shrinkage 15.11 %, and UCS 31.31(kpa). All tested soil samples were found with high degree of expansion and low subgrade strength. The four soils have almost similar engineering properties. From the each soils based on parameters obtained from test result of free swell and UCS (kpa) Ifa bula I was selected for stabilization. The Ifa bula I soil sample was stabilized using 4, 6, and 12% of Waste of ceramic tiles, 2, 4, and 6% of Waste of tire pieces and using 2, 4, 8, and 12% of combined Wastes of ceramic tiles with that of tire pieces by dry weight of soil. The improvement of sub grade soil properties were increased with increased ratios of Wastes of ceramic tiles and tire pieces. The maximum improvements on engineering properties were observed on soil CBR value with its addition up to 2%T+2%C and there onwards decreased with further increase in combination of Waste tire piece and ceramic tile. Percentage improvement in CBR value of weak subgrade was 1181% improved. The result indicated that the two stabilizers were very effective in improving index parameters than strength parameters. The results of this study show that the Wastes of ceramic tiles and tire pieces are promising in improving sub grade soils. The present study was conducted by taking limited parameters on stabilization by tires and ceramic waste.