Lime stabilization of expansive soil from Sergipe - Brazil

¹ Universidade Federal de Sergipe, Department of Civil Engineering, Av. Marechal Rondon, 49100-000 São Cristóvão, Brazil
² Universidade Federal de Campina Grande, Department of Civil Engineering, R. Aprígio Veloso, 58429-900, Campina Grande, Brazil
³ Universidade Federal do Rio Grande do Norte, Department of Civil Engineering, Lagoa Nova, 59078-970, Natal, Brazil

^a Corresponding author: rafaellapradoleite@gmail.com

Abstract

Expansive soils are characterized by volumetric changes caused by variations in moisture. They can cause several damages to civil constructions, especially to lightweight structures, including cracks and fissures. Chemical stabilization through addition of lime is one of the most effective techniques used to treat this type of soil. Due to cationic exchanges, lime can significantly reduce swell potential. This research studied a disturbed sample of expansive soil collected in Nossa Senhora do Socorro – Sergipe, Brazil, through the following laboratory tests: sieve and hydrometer tests, Atterberg Limits, compaction, free swell and swell pressure. All direct and indirect methods mentioned in this paper indicated that the natural soil presented high to very high degree of expansion, which reached approximately 20% of free swell and nearly 200 kPa of swell pressure. In order to evaluate the effect of lime, the same tests were conducted in soil-lime mixtures, using lime contents of 3%, 6% and 9%. The results confirmed the efficiency of lime stabilization. It was noted that, as lime content increased, there was reduction of clay fraction and increment of silt fraction; plasticity index decreased to nearly its half; compaction curve was displaced; and free swell and swell pressure reduced significantly.