Swelling potential of a stabilized expansive soil: a comparative experimental study

The efficiency of typical chemical and mechanical soil stabilization techniques in mitigating the swelling problem of an expansive soil is investigated through a comprehensive experimental study. Chemical stabilization was generated by traditional agents consisting of lime and cement, and by a commercially branded polymer (CBR PLUS). Mechanical stabilization was applied by means of fiber-reinforcement and swell–shrink cycles. Chemically-treated and fiber-reinforced soil samples were tested for swelling potential in a conventional oedometer apparatus; while swell–shrink cycles were applied using a modified temperature-controlled oedometer. Swell–shrink cycles were applied under room temperature for wetting cycles while the drying process was conducted under a constant temperature of 40 ± 5 °C, and swelling and shrinkage potential were recorded during successive cycles to a point in which swell–shrink equilibrium was attained. Typical strength tests were also conducted for each stabilization scenario which led to maximum reduction in swelling potential. In addition to the experimental program, the swell–time relationship for various stabilization scenarios was simulated using a two-parameter rectangular hyperbola function (2P-RH). Results indicated that all of the proposed stabilization scenarios can guarantee a significant reduction in swelling potential. In the case of lime and cement, reduction in swelling potential was observed to be a function of agent percentage and curing time; whereas for polymer-treated samples the effect of curing was found to be insignificant. Regarding fiber-reinforced samples, reduction in swelling potential was a function of fiber percentage, aspect ratio and fiber tensile strength. Overall, traditional agents proved to be more effective compared to non-traditional techniques. The proposed non-traditional methods, however, displayed promising results posing as great alternatives to lime and cement.Amin Soltani, Abbas Taheri, Mehdi Khatibi, A. R. Estabrag