Abstract:
Expansive soil is one of soil type, which experiences significant volume change upon rainy
and dry season. When it gets water, it swells and when it is dry, it became shrinking. It is
not suitable for all type of infrastructure. The seasonal movement of such materials causes
contract of the ground surface in the dry season and expand during the rainy season, which
is the most challenging tasks for the geotechnical engineers. Therefore, to overcome such
problems of expansive soil the stabilization method is very crucial. Therefore, blending
expansive soil with granite stone dust stabilization method can improve the geotechnical
properties of expansive soil and to increases the bearing capacity of soil used for sub grade
and Shallow foundation of the structure. The purpose of this study is treating the expansive
soil with stone dust to minimize damage that can happen due to the problem of expansive
soil. This study focused on the Engineering properties of clay expansive soils blended with
stone dust to improve the geotechnical properties of expansive soils by adding at 5%, 10%,
15%, 20%, and 25% Percentages of stone dust. The study area is in Jimma town. In this
study, a Soil sample was excavated at 1.5m and 3m. Laboratory tests were conducted to
determine moisture content, free swell test, grain size analysis, specific gravity,
Hydrometer test, Atterberg limits, and compaction test; California Bearing Ratio and CBR
swell tests, UCS and Complete silcate analysis test. Depending on the tests to be conducted
in the laboratory the optimum percentage of stone dust are obtained at 15%. The
Laboratory test result indicates the addition of stone dust to expansive soil improves the
strength of the expansive soil. The OMC Varies from 31.4 to 17.653 and the MDD also
varies from 1.327 g/cm3 to 1.644g/cm3.This value indicated that there is improvement in
the engineering properties of expansive soil. The CBR of the value is increases from the
2.52% to 27.3%. The addition of stone dust highly increases the plastic limit and decreases
the liquid limit, plasticity index, and shrinkage index of the expansive soil sample.
Generally, it as the addtion of stone dust ratio increased the FS, LL, PL, OMC, CBR swell
decreased and inversely the PL, MDD, CBR and UCS are increased and recommended that
blending of expansive soil with stone dust can be used to increase the strength capacity of
foundation and subgrade.in addition the stone dust can be gained with low cost, locally
available and finally makes our environment to became safe.
