Aspects Affecting Calcium Carbonate Precipitation During the Carbonation of Soils

Chemical stabilization is a widely used method for improving the engineering properties of soils. It solves challenges such as low strength, high compressibility, and excessive moisture sensitivity. This technique involves adding chemical agents to the soil to enhance its physical and mechanical properties, making it more suitable for construction and infrastructure projects. Carbonation is a reaction in which 𝐶𝑂2 diffuses through lime-treated soil, gets dissolved in the pore water, reacts with the dissolved 𝐶𝑎2+, and produces calcium carbonates (𝐶𝑎𝐶𝑂3), which serve as a binder. Soil carbonation is a technique used to improve the strength of sub-grade to support pavements and foundations through cation exchange capacity rather than the cementing effect brought by the pozzolanic reaction. Low binder content critically impacts the effectiveness of carbonated soils used in ground improvement. Understanding and ensuring that the maximum possible amount of 𝐶𝑎𝐶𝑂3 binder is produced in carbonated soils are essential for optimizing their performance in various geotechnical applications. This research elucidates that the binder produce significantly affects the level of soil carbonation, impacting both the efficiency of the carbonation process and the quality of the resulting soil stabilization. Extensive research has been conducted on how binder content generated affects the mechanical properties (Unconfined Compressive Strength, and Stiffness) of carbonated soil samples at different void ratios with varying lime content of 7%, 10%, and 15% using the Instron machine. An Advanced Dynamic Triaxial Testing System (DYNTTS) and Instron 5900R machine were used to investigate changes of the stiffness of reconstituted carbonated soil and improvements of mechanical strength. The findings indicate that high binder content results in high mechanical strength and stiffness changes with time. This research contributes valuable insights into using high-purity lime for chemical stabilization.