Effects of Two Different Polymers and Calcium Chloride Solution on the Swelling Behavior of an Expansive Soil

In this research, the swelling properties of an expansive soil (bentonite) were investigated through experimental tests, focusing on the effects of two different polymers: polyethylene oxide or polyethylene glycol (PEO) and polyacrylamide (PAM), as well as calcium chloride (CaCl2) solution. The soil samples were compacted by static compaction in a special mold to create consistent samples. Subsequently, the samples were subjected to flooding with distilled water, solutions of the two polymers, or a CaCl2 solution at concentrations of 2, 4, 6, and 8 g/L. The swelling potential and swelling pressure of the samples were measured to assess their response. The results showed that the polymer solutions effectively reduced both the swelling potential and swelling pressure of the samples, indicating an interaction between the polymers and the soil. This interaction was further supported by the scanning electron microscopy results. Furthermore, the type of flooding fluids (polymer or CaCl2 solution) and its concentration were found to significantly influence both the swelling potential and swelling pressure. Comparing the results obtained, it was observed that PEO exhibited a greater reduction in soil swelling compared to PAM. Additionally, the CaCl2 solution showed a more pronounced effect on soil swelling compared to both polymers.