Conservation method of relics soil based on carbonization principle

The phenomenon of surface cracking and falling off of newly restored soil sites, results in inferior appearance quality compared to old sites. In response to the diseases of newly restored soil sites, combined with the requirements of mechanical construction, a 2% concentration of sodium methylsilicate (waterproofing agent) was added to the simulated site soil. Based on the principle of lime carbonation, mechanical and hydraulic performance comparative tests were conducted on simulated site soil samples with different lime parameters, CO₂ concentrations, and curing times. The experimental research results show that: (1) After adding lime and sodium methylsilicate, the water stability and disintegration performance of the soil sample are more ideal. Under the condition of CO₂ concentration of 5%, sodium methylsilicate and lime have basically completed carbonization. After 24 hours of curing, good capillary water absorption performance can be achieved, and good disintegration resistance can be achieved after 72 hours of curing. (2) Increasing the lime content, CO₂ concentration, and curing time can increase the amount of CaCO₃ produced after sample carbonization, thereby improving its shear strength and compressive strength, and the contribution of CO₂ concentration is greater than that of curing time. (3) When the concentration of CO₂ in the air is 15%, the compressive strength of the sample increases slowly and tends to stabilize after a curing time of more than 72 hours. That is, after sufficient reaction between lime and sufficient CO₂ in the air (about 72 hours), the compressive strength of the sample approaches the optimal level. This research could provide new ideas for the protection of soil sites.