The present paper sets out a comparative analysis of carbon emission and economic benefit of different performance gradients solid waste based solidification material (SSM). The macro properties of SSM were the focus of systematic study, with the aim of gaining deeper insight into the response of the SSM to conditions such as freeze-thaw cycles, seawater erosion, dry-wet cycles and dry shrinkage. In order to facilitate this study, a range of analytical techniques were employed, including scanning electron microscopy (SEM), X-ray diffraction (XRD) and mercury intrusion porosimetry (MIP). The findings indicate that, in comparison with cement, the carbon emissions of SSM (A1) are diminished by 77.7 %, amounting to 190 kg/t, the carbon-performance ratio (24.4 kg/ MPa), the cost-performance ratio (32.1RMB/MPa) and the carbon-cost ratio (0.76kg/RMB) are reduced by 86 %, 56 % and 68 % respectively. SSM demonstrated better performance in terms of freeze-thaw resistance, seawater erosion resistance and dry-wet resistance when compared to cement. The dry shrinkage value of SSM solidified soil was reduced by approximately 35 % at 40 days compared to cement solidified soil, due to compensatory shrinkage and a reduction in pores. In contrast to the relatively minor impact of seawater erosion and the moderate effects of the wet-dry cycle, freeze-thaw cycles have been shown to cause the most severe structural damage to the micro-structure of solidified soil. The conduction of durability tests resulted in increased porosity and the most probable aperture. The increase in pores and micro-structure leads to the attenuation of macroscopic mechanical properties of SSM solidified soil. The engineering application verified that with the content of SSM of 50 kg/m, 4.5 % and 3 %, the strength, bearing capacity and bending value of SSM modified soil were 1.9 MPa, 180 kPa and 158, respectively in deep mixing piles, shallow in-situ solidification, and roadbed modified soil field.

Silt soil is widely distributed in coastal, river, and lacustrine sedimentary zones, characterized by high water content, low bearing capacity, high compressibility, and low permeability, representing a typical bulk solid waste. Studies have shown that cement and ground granulated blast furnace slag (GGBFS) can significantly enhance the strength and durability of stabilized silt. However, potential variations due to groundwater fluctuations, long-term loading, or environmental erosion require further validation. This study comprehensively evaluates cement-slag composite stabilized silt as a sustainable subgrade material through integrated laboratory and field investigations. Laboratory tests analyzed unconfined compressive strength (UCS), seawater erosion resistance, and drying shrinkage characteristics. Field validation involved constructing a test with embedded sensors to monitor dynamic responses under 50% overloaded truck traffic (simulating 16-33 months of service) and environmental variations. Results indicate that slag incorporation markedly improved the material's anti-shrinkage performance and short-term erosion resistance. Under coupled heavy traffic loads and natural temperature-humidity fluctuations, the material exhibited standard-compliant dynamic responses, with no observed global damage to the pavement structure or surface fatigue damage under equivalent 16-33-month loading. The research confirms the long-term stability of cement-slag stabilized silt as a subgrade material under complex environmental conditions.

Cement-stabilized soil in coastal soft soil regions is essential for infrastructure construction. However, under the combined effects of seawater erosion and cyclic loading, cement-stabilized soil often faces issues such as strength degradation, reduced durability, and stiffness softening. To enhance the engineering properties of cement soil, this study utilized nano-Al2O3 as a modifier. The effects of nano-Al2O3 on the dynamic properties of cement soil under various erosion environments were assessed using the GDS dynamic triaxial system. Furthermore, scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests were performed to study the microstructural changes in cement-stabilized soil modified with nano-Al2O3 subjected to seawater erosion. The results indicate that nano-Al2O3 significantly improves the resistance of soil to deformation. As the content of nano-Al2O3 increases, the dynamic strain of cement-stabilized soil initially decreases and then increases, while the dynamic shear modulus first increases and then decreases, showing optimal performance at a 0.25% content. Seawater erosion severely weakens the strength and stiffness of cement-stabilized soil; as erosion concentration increases, dynamic strain increases, and dynamic shear modulus decreases. Nano-Al2O3 improves the strength of cement-stabilized soil and mitigates the negative impacts of seawater erosion through pozzolanic reactions and filler effects.