In order to solve the problem of solid waste soda residue (SR) environmental pollution and resourceful utilization, lime soil modified by high content soda residue (LSMHCSR) is prepared by solid waste SR, lime and soil. In this paper, the basic characteristics of SR and the mechanical properties of LSMHCSR were tested, and the enhancement mechanism of LSMHCSR was analyzed. The test results showed that: (1) SR is mainly composed of CaCO₃, Ca(OH)₂ and CaCl₂, with high natural moisture content, which is not recommended as a separate engineering filler; (2) As the SR content gradually increased, the optimum moisture content of LSMHCSR gradually increased, with the maximum dry density first increasing and then decreasing; (3) With SR content in the range of 10% to 30%, both 7d and 28d UCS of LSMHCSR increased first and then decreased, reaching the maximum under 15% SR, with the increase as high as 36.9% and 37.2%, respectively. The optimal material mix ratio was SR:lime:soil = 15%:6%:85%; (4) An appropriate amount of SR could effectively promote the physical filling, cementation, crystallization and carbonization, and pozzolanic reactions of the material, and the resulting cementing substances, such as CaCO₃ crystals, C-H-S and N-A-S-H, could improve the material strength. However, under excessive SR amounts, the excess SR did not react, with the material strength reduced. Based on the engineering benefit analysis of the test section, lime soil modified by high content SR can effectively alleviate the road material supply shortage, soil erosion and solid waste pollution problems, demonstrating remarkable technical, economic and social benefits and enjoying a good prospect of application and promotion.

In this paper, hydroxypropyl methylcellulose (HPMC) is used as a new additive for porous vegetarian concrete (PVC) to improve its void structure and strength. The effect of the HPMC on the fluidity of the mortar was first investigated by a viscosity test. Then the cement hydration process was determined for analyzing the effect of the HPMC on the strength and durability of the hardened PVC. Subsequently, experiments to investigate the mass transport and compressive strength characteristics, as well as the vegetarian properties, of the concrete were carried out. The results show that the bonding forces between the recycled aggregates and packing layer are elevated by viscosity improvement. The viscocity and flowability are significantly related to the dosage of HPMC from 0.0‰ to 0.3‰. The harden time is also delayed while the content of HPMC increases.The segregation phenomenon caused by the recycled aggregate powder in porous concrete could also be relieved by adding HPMC. The durability of PVC in the wetting–drying cyclic test is significantly improved by incorporating HPMC. The results of the vegetarian test also prove that, with HPMC mixing, sufficient space would be created in porous concrete, which is more suitable for plant growth due to a large number of existing pore channels.