Magnesia carbonation can be adopted as a soil solidification technology for geotechnical engineering. Recent studies have shown that urea decomposition under the catalyzation of ureolytic bacteria can provide a carbon source for magnesia carbonation. Although many related studies have been reported, the mechanical behaviour of the magnesia solidified soil, especially its durability and long-term performance, still require further deep investigations. Besides, the use of plant urease instead of bacteria for magnesia carbonation is also of research interest and requires further studies. In this study, we used crude soybean urease for the catalyzation of urea decomposition in order to provide carbon source for magnesia carbonation (soybean urease intensified magnesia carbonation, SIMC). The mechanical behaviour and durability of SIMC solidified soil under drying-wetting and soaking conditions in acid rain solution were investigated. For SIMC samples, the addition of urea and urease as internal carbon sources led to a much higher strength compared with those without them. The optimum urea concentration was 2 mol/L, and higher concentrations could have negative impact on the strength. As for magnesia, the highest strengths were obtained when the addition was 8 %. During the drying-wetting cycles and soaking tests with acid rain water, there was a generally moderate decreasing trend in strength for the SIMC samples with more drying-wetting cycles or soaking durations. However, the strength reduction ratio, which was defined as the long-term strength in acid environment to that in neutral environment, was much higher compared to the PC samples, implying a much stronger resistance to acid rain water. The mineralogical analysis revealed that hydrated magnesium carbonates were the major effective cementing materials.

来源平台：TRANSPORTATION GEOTECHNICS