Abstract
Expansive soil is considered a potential natural hazard, which can cause extensive damage to structures if not adequately treated. One of the mitigation techniques of such soil is to mix it with lime. This paper aims to study the effect of the limestone and hydrated lime on the behavior of the highly expansive clay. Ca bentonite is used as the highly expansive clay. The bentonite has been mixed with lime in varying amount ranging from 0 to 10%. Each bentonite-lime sample was remolded at modified AASHTO density and optimum moisture content. Four series of tests were performed on each mixture included: swelling potential, swelling pressure, California bearing ratio (CBR), and unconfined compression strength test. The results of the study showed that mixing limestone and hydrated lime with expansive clay reduces swelling potential and swelling pressure. There is a further reduction in the swelling pressure and swelling potential with increasing lime percentage. But mixing hydrated lime with clay causes significant reductions in swelling potential and swelling pressure. The swell potential decreases from 34.5 to about 26.5% and 1% in case of clay sample mixed with 10% limestone and 10% hydrated lime, respectively. The non-treated bentonite implies high values of CBR and unconfined compressive strength. The limestone has a negative effect on the strength of the clay. While the hydrated lime causes increases in the strength of the clay. The strength of the clay-hydrated lime mixtures has further increases with increasing lime content and curing time. Copyright 2015 Saudi Society for Geosciences