Abstract:
Expansive clay soil is one of the most abundant soil types in Ethiopia; it primarily causes
significant damage to structures like buildings, pavements, and bridges. Some land areas in Jimma
City covered with expansive soil. The problematic nature of such soil can improved by employing
chemical stabilization techniques such as lime, cement, and bituminous stabilization. However,
these methods are expensive to develop and apply in countries such as Ethiopia. The reason
enforces to use locally available, low-cost, and environmental friendly materials to get stable
subgrade soil. Hence, the objective of this study was to investigate the mixed effect of varying
percentages (10% ,15%and20%) of ceramic dust waste and (0.5% to2.5%) of jute geotextile fiber
every 0.5%increament by weight of dry soil on the strength of expansive subgrade soil and
stabilization conducted as matrix combination. The sampling technique used for this research was
a purposive sampling, which is non– probability method. Three sample areas selected and samples
were taken, and then their properties were investigated. The Laboratory tests conducted were
Moisture content, particle size analysis, Atterberg limits, free swell, specific gravity, compaction,
California Bearing Ratio and Unconfined compression strength tests. Shrinkage limit from Liquid
Limit vs Plasticity index chart, soil expansiveness by formula and soils swelling potential
conducted for untreated while strength tests conducted only for treated soil. The result from
laboratory tests have shown that the soil sample belonged to the A-7-5 class according to
American Association of State Highway and Transportation officials and CH (inorganic clay of
high plasticity) according to the Unified Soil Classification System and the soil rated as poor
(unsuitable) subgrade materials.
For stabilized soil by different combinations, the one, in which the maximum improvement was
achieved, at a combination of 1.5%Jute Geotextile Fiber with 20%Ceramic Dust Waste Powder.
The results revealed that Maximum dry density, California Bearing Ratio, and Unconfined
compression strength were increased from 1.3g/cc to 1.57g/cc,1.03% to 8.4% and74.80KPa to
538.88Kpa, respectively for immediate cure while 660.65KPa unconfined compressive strength
for seven day curing. Optimum moisture content and Swell decreased from 30.05% to 22.64% and
10.07% to 1.04%, respectively. For enhancing the strength of expansive subgrade soil, a suitable
combination of 20% of waste ceramic dust and 1.5% of jute geotextile fiber by weight of dry soil
is optimum and recommended.
