Evaluating the influence of morphology and normalized montmorillonite content and chemical composition on swelling characteristics of expansive soils

In the present study, 2D relationships are developed for swelling properties (swelling potential, S_a, and swelling pressure, S_p) with chemical parameters (sodium (Na) and calcium (Ca) contents in their total (T), and leachable (L) forms) and montmorillonite content (MMC). For this purpose, extensive experimental data are produced and the same is used for establishing relationships. The maximum value of MMC, S_a and S_p of soils used in the study are measured as: 44%, 18%, and 110 kPa, respectively. Both MMC and chemical composition manifested marked influence on S_a than on S_p. The variations of S_a and S_p found to be non-linear in nature with MMC/Na_(T/L), whereas in the case of MMC normalized with Ca there is a reversal effect on swelling properties. Concerning the two forms of Ca and Na contents, distinct influence of them on S_a and S_p is perceived. It is particularly found that, as MMC varies so does Ca and Na contents in soils, understandably confirming existence of an intrinsic interrelation between mineralogical and chemical parameters. Such in-depth understating about micro-level behavior will greatly aid in the selection appropriate additive contents for stabilization as well as designing appropriate foundation systems in expansive soils.