Column experiments to study the thermo-hydro-mechanical-chemical behavior of sensitive marine slay subgrade soil treated with lime

Column experiments were conducted in this study on treated and untreated sensitive marine clay to understand the evolution of the coupled thermal (T), hydraulic (H), mechanical (M), and chemical (C) processes that occur in the treated and untreated marine clay by monitoring the soil samples over a period of 28 days. Three columns in which sensors were placed within the compacted soil samples and a dial gauge at the top were set-up to allow monitoring of the evolution of the THMC processes. Nine other columns were also prepared and set-up from which samples for extensive testing were obtained after 1, 3, 7, and 28 days. The mechanical properties of the soil increased significantly due to the lime treatment in which pozzolanic reactions occurred. The study showed that the improved mechanical properties were coupled with the chemical reactions—monitored through electrical conductivity, temperature evolution within the column and suction which developed with time. Properties such as the hydraulic conductivity were equally affected, to which pore refinement as a result of lime hydration, was attributed. The coupled THMC behavior was noted to have been highly dependent on the hydration of lime. To understand the behavior of treated pavement subgrades, the effects of the coupled process presented in this study need to be understood to further design cost effectively and have pavements of long service lives.