Understanding the role of Ca2+, Na+ on swelling behaviour of natural expansive soils: a field application perspective

Swelling behaviour is the prime hindrance for effective utilization of expansive soils as a geomaterial. To alleviate such behaviour, stabilization with a suitable additive is essential. However, the current practice of additive and stabilization selection technique to treat the expansive soils predominantly relies on geotechnical properties, in particular on consistency limits. The present paper aims at demonstrating the role of chemical constituents on swelling properties in a comprehensive way. Elaborate tests to determine the swelling and chemical constituents are carried out, and based on the obtained results, interrelations between them are developed. The analysis of results revealed the maximum swelling occurrence at Na T of 0.4–0.7%, Ca T of 4–5.5%, total CEC of 45–70 meq/100 g, and (Ca/Na) T of 15.75, respectively. The results portray that swelling in clays is minimal when Na T 5.5%, and total CEC