Comparative Study on the Enhancement of Soil Cement Strength Using Bentonite and Polyurethane Foam

Abstract

The construction of buildings and infrastructure on soft ground, such as soft Bangkok clay, presents significant geotechnical challenges due to its high compressibility, high settlement potential, and low bearing capacity. Consequently, soil-cement stabilization is widely applied to improve the strength of soft ground. This study evaluated the effects of bentonite and polyurethane foam as additive admixtures to increase the strength of soil cement. The primary purpose was to investigate compressive strength. Moreover, Scanning Electron Microscopy (SEM) was employed to examine the microstructure, which supports the primary purpose. The control specimen consisted of 80% soil and 20% cement by dry weight of the total soil-cement mixture. Bentonite and polyurethane foam contents of 10%, 20%, and 30% by dry weight of the total soil-cement mixture were investigated and added as additive admixtures to the soil-cement mixture. The results showed that adding bentonite and polyurethane foam can increase the strength of soil cement. The suitable ratios of bentonite and polyurethane foam were 30% and 10% by dry weight of the total soil-cement mixture, respectively. Moreover, both bentonite and polyurethane foam can increase compressive strength. This approach offers a pathway to more efficient, sustainable soil-cement stabilization methods to improve soft soils.