Testing surfactants as additives for clay improvement: compaction and suction effects

Abstract

This paper presents an exploratory study on surfactants as additives to improve soil properties. It is hypothesized that surfactant molecules populate the air-water interfaces reducing surface tension and suction thus allowing a control of the mechanical response of the soil. Suction measurements by means of a high suction tensiometer, compaction tests and Atterberg limits were conducted in mixtures of sand and kaolin, with and without a surfactant solution. The results revealed a prominent effect on suction, but to a lesser extent on the Atterberg limits and compaction behavior (the maximum dry density). This targeted effect of the surfactants suggests its molecules populate, not only the air-water interfaces decreasing surface tension, but may be adsorbing to the clay particles and forming micelles in the pore water as well. Therefore the interplay between the three may influence the soil behavior.