Using a Polycarboxylic Acid-Based Surfactant to Improve the Quality of Cement-Treated Ground

Abstract

When cohesive surface soils are treated to create cement-based ground improvements, suppressing the aggregation of the clay particles with the cement-based solidifying material particles is an important consideration. Herein we evaluated a method that reduces the variation in the soil improvement body’s strength by the generation of an electrical repulsive force between the particles due to the surfactant for aggregation suppression. The aggregation suppression mechanism was first verified by measuring the ζ-potential of the particles. The effect of reducing the variation in the soil improvement body strength was verified with an unconfined compression test using a specimen manufactured by indoor mixing. Finally, the effectiveness of the methodology was evaluated with on-site testing. Upon adding a surfactant, positively charged cement-based solidifying material particles have their potentials reduced, thereby becoming negatively charged. Therefore, electrical repulsion operates between these particles and the negatively charged clay particles, thereby preventing aggregation, increasing the fluidity of the soil-cement slurry, and reducing the variation in the strength of the soil improvement body. Finally, the effectiveness of the methodology was confirmed by on-site testing.