Stabilization of expansive soil using cementing material from rice husk ash and calcium carbide residue

Abstract

In order to reduce geological disaster caused by expansive soil and utilize waste resources, a cementing material combined with rice husk ash(RHA) obtained from biomass power plants and calcium carbide residue(CCR) gained from acetylene plants, was used for stabilization of expansive soil. Based on compressive and flexural strength of RHA-CCR mortars, mixing ratio of RHA/CCR was adopted as 65:35 by weight for soil stabilization. Through a series of tests, the swelling-shrink and strength properties of stabilized expansive soil have been investigated. With increase of binding content, curing time and initial water content, swelling potential, swelling pressure, crack quantity and fineness of expansive soil lowered remarkably. Meanwhile, unconfined compressive strength, cohesion and internal friction angle improved significantly after adding RHA-CCR. From the perspective of strength improvement, blending content of 15% and initial water content of 1.2 times the optimum moisture content was recommended for stabilizing expansive soil. The mechanism of RHA-CCR to stabilize expansive soil involved replacement efficiency, coagulation reaction and ion exchange. In the future, stabilization of expansive soil using RHA-CCR will be highly concerned because of excellent performance, lowered construction and disposal costs, reduced environmental pollution.