Stabilization of Expansive Soil with Polyvinyl Alcohol and Potassium Carbonate

Abstract

Expansive soils have great volume change potentials with water content changes, which is problematic to facilities. Great efforts have been spent on finding proper methods to stabilize expansive soils, but these stabilizers all had limitations. The Polyvinyl alcohol (PVA) and K2CO3 combination was proposed in this paper. Free swell tests, oedometric tests, unconfined compression tests, and direct shear tests were performed to investigate the effectiveness of the PVA and K2CO3 combination to control the volumechangeandincreasethesoilstrength.Microstructuresofthenaturalexpansivesoilandthestabilizedsoilwerealsostudied with SEM photos.SEM photos showed a homogenous and densemicro structure after stabilization.Inaddition,alaboratorysoil column model was built to study the ability of this stabilizer combination to stabilize expansive soils by directly spraying the solution on the ground surface.All thesetestresultsshowthat the combination of PVAand K2CO3 is able to effectively stabilize the natural expansive soil and increase the shear strength.It is possible to directly spray the stabilizer solution on the soil surface to form a relatively thick layer of the stabilized expansive soil.