Utilization of Cementitious Material from Residual Rice Husk Ash and Lime in Stabilization of Expansive Soil

Abstract

Geological disastersoftenoccurduetoexpansionandshrinkagepropertiesofexpansive soil.Thispaperpresentsacementitious material combinedwith ricehuskash(RHA)obtained frombiomass powerplantsandlime tostabilize expansivesoil. Basedon compressive and flexural strength of RHA-lime mortars, blending ratio of RHA/lime was adopted as 4:1 by weight for soil stabilization.WhenmixproportionofRHA-limemixturevariedfrom0%to20%,specificsurfaceareaofstabilizedexpansivesoil decreased dramatically and medium particlesize increased. The deformationand strength propertiesof stabilized expansive soil wereinvestigatedthroughswellingtest,consolidationtest,unconfinedcompressiontest,directsheartest,andsoon.Withincrease inRHA-limecontentandcuringtime,deformationpropertiesincludingswellingpotential,swellingpressure,compressionindex, crack quantity, and fineness of expansive soil lowered remarkably; meanwhile, strength properties involving unconfined compressive strength, cohesion, and internal friction angle improved significantly. Considering engineering performance and cost,mixproportionof15%andinitialwatercontentof1.2timesoptimummoisturecontentwererecommendedforstabilizing expansive soil. In addition, effectiveness of RHA-lime to stabilize expansive soil was achieved by replacement efficiency, coagulation reaction, and ion exchange.