Abstract:
Expansive soils are known for their volume changes with seasonal moisture fluctuations. It
swells when it gets wet and shrinks during the dry season. Seasonal changes in the volume of
expansive soil cause significant damage to infrastructure. Due to this complex behavior,
expansive soil should be treated properly or avoided when used as foundation soil and in
subgrade road construction. This study is aimed at improving the bearing capacity of the
expansive soils in Fiche town by stabilizing them with cement and lime. Two representative
samples were collected from selected sites in Fiche town using purposive sampling. Various
geotechnical tests were carried out to characterize the expansive soil. The test results show
that both soils were found to be highly plastic clay soils (CH or A-7-5). After the soil was
checked to be expansive soil, different percentages of cement and lime were added to treat
the natural soil. The improvement was evaluated by adding 3%, 5%, 7%, and 9% of hydrated
lime and 3%, 5%, 7%, 9%, 11%, 13%, and 15% of cement by weight. The findings of the
laboratory tests indicate that the plastic index of the naturally expansive soils decreased with
the addition of cement and lime, on average, from 49.1% to 13.2% for cement and from
49.1% to 10.9% for lime stabilizers. The value of CBR increased from 1.48% to 16.5% and
from 1.48% to 9.8% when stabilized with cement and lime, respectively. Generally, the
addition of cement and lime resulted in significant improvements in CBR, free swell, CBR
swell, plastic index, and compaction characteristics. In this study, the minimum requirement
requested by the ERA standard was achieved with 7% of cement and lime addition. Hence,
from the above-mentioned results, it was concluded that the use of cement and lime improves
the engineering properties of expansive soil. Additionally, the researcher would recommend
that further research should concentrate on the impact of cement and lime as stabilizers on
consolidation properties
