Optimization of the Atterberg Limits on expansive soil stabilized with chitosan biopolymer

Abstract

Pavement deterioration can be caused by expansive road subgrade material. Swelling properties are one of the problems on expansive soils. The swelling properties can be decreased by stabilization using additives. The potential of using chitosan biopolymer for soil improvement is attractive due to environmental friendliness and sustainability. This research was conducted to determine the effect of chitosan biopolymer from shrimp shell waste on the Atterberg Limits of expansive soil. This test can be used as an initial assessment of soil strength and stiffness parameters. The Atterberg Limits test was carried out by mixing chitosan biopolymer with a ratio of 0.05%; 0.10%; 0.15%; and 0.20% to the dry weight of the expansive soil. The study’s results showed that adding chitosan biopolymer with a ratio of 0.1% was the most effective in reducing the plasticity index by up to 67% and increase in the shrinkage limit value which is greater than 12%, making the degree of expansion non-severely. The use of chitosan biopolymer is also expected for soil pollution control and remediation.