The organic matter in soft clay tends to affect the properties of cement-stabilized soil. The influence degree of different organic matter varies. In this paper, the influence weights and mechanism of the main organic matter components fulvic acid and humic acid on the mechanical properties of cemented soil were investigated. Impacts of FA/HA (fulvic acid/humic acid) values and curing time on the unconfined compressive strength, deformation characteristics, and microstructure of cemented soil were explored through the unconfined compressive strength test and electrical resistivity test. The results show that with the increase of FA/HA, the unconfined compressive strength of cemented soil gradually decreased and the plastic properties enhanced. The increase in curing time changed the stress-strain relationship of cemented soil, and some specimens showed brittle damage. The initial resistivity and structural property parameters of cemented soil gradually decreased with the increasing FA/HA value and increased with the increase of curing time. It revealed the influence law of FA/HA and curing time change on the microstructure of cemented soil. Based on the experimental results, the quantitative relationship equations between FA/HA and curing time and unconfined compressive strength, failure strain, deformation modulus, and resistivity were established.

This study, from the perspective of resource utilization and carbon sequestration, developed a novel lightweight carbonated solidified slurry material using reactive magnesium oxide (MgO), ground granulated blast furnace slag (GGBS), and carbide slag as stabilizers, with carbonation induced by a CO₂ foaming method. The physical and mechanical properties of the material were investigated. Based on the optimal mix proportion, the effects of MgO content, CO₂ foam dosage, and stabilizer dosage on wet density, flowability, moisture content, and unconfined compressive strength were analyzed. The results indicate that wet density increases with increasing MgO and stabilizer content but decreases with increasing CO₂ foam dosage. Flowability decreases with increasing MgO and stabilizer content but improves with a higher CO₂ foam dosage. Unconfined compressive strength increases with curing age and stabilizer content but decreases with increasing CO₂ foam dosage. Additionally, prolonged curing enhances both moisture content and unconfined compressive strength. These findings provide a theoretical basis for engineering applications.

Global urbanization has led to massive generation of high-water-content waste slurry, creating serious environmental challenges. Conventional treatment methods are costly and unsustainable, while cement-based foamed lightweight soils typically exhibit low strength and limited CO₂ sequestration. To address this issue, this study proposes a novel stabilization pathway by integrating a MgO–mineral powder–carbide slag composite binder with CO₂ foaming–carbonation. The approach enables simultaneous slurry lightweighting, strength enhancement, and CO₂ fixation. A series of laboratory tests were conducted to evaluate flowability, density, compressive strength, and deformation characteristics of the carbonated lightweight stabilized slurry. Microstructural analyses, including SEM and XRD, were used to reveal the formation of carbonate phases and pore structures. The results showed that MgO content strongly promoted carbonation, leading to denser microstructures and higher strength, while mineral powder and carbide slag optimized workability and pore stability. Orthogonal testing indicated that a mix with 25% mineral powder, 12.5% MgO, and 7.5% carbide slag achieved the best performance, with unconfined compressive strength up to 0.48 MPa after carbonation. Compared with conventional cement- or GGBS-based foamed lightweight soils, the proposed system exhibits superior strength development, improved pore stability, and enhanced CO₂ sequestration potential. These findings demonstrate the feasibility of recycling high-water-content waste slurry into value-added construction materials while contributing to carbon reduction targets. This study not only provides a sustainable solution for waste slurry management but also offers new insights into the integration of CO₂ mineralization into geotechnical engineering practice.

The high carbon emissions associated with cement-based materials in lightweight foamed soils have become a significant environmental concern. In addition to this applied problem, there is also a scientific challenge: current studies of carbon–magnesium reactions in lightweight carbonated soils (LCSS) lack multiparameter predictive models, which are essential for understanding the coupled effects of MgO dosage and CO₂ foam content on material performance. This study addresses this gap by systematically investigating the influence of MgO and CO₂ foam on the strength, resistivity, and carbonation behavior of LCSS. A multiparameter regression model was developed to predict these properties, and its statistical significance and predictive accuracy were verified. The results show that MgO dosage strongly promotes carbonation and strength development, while CO₂ foam content primarily regulates porosity and carbonation degree. The established model provides reliable predictions of LCSS performance and offers a scientific basis for optimizing carbon–magnesium reactions in sustainable soil stabilization.

Remediating heavy-metal pollution in flowing groundwater is challenging because powder adsorbents may agglomerate or wash away, while static tests do not represent dynamic transport. To address these limitations, a PET-Fe-BDC composite geotextile was prepared by in situ synthesis following PAM pretreatment and evaluated for Pb(II) and Cd(II) retention in continuous soil-column seepage experiments. Compared with unamended soil, the composite-geotextile-amended system markedly retarded the downward migration of both ions. In the 0–5 cm retardation layer, cumulative removal efficiencies exceeded 80% up to t_e′, and the breakthrough times of Pb(II) and Cd(II) increased to approximately 6.9 and 6.4 times those in the unamended system, respectively. Thomas, Yan, Clark, and Yoon–Nelson models were used to describe the observed breakthrough behavior. The Yan model provided the most consistent empirical description across the tested curves. The Thomas model closely described the unamended-soil curves and the composite-system Cd(II) curve but showed weaker agreement for composite-system Pb(II), whereas the Clark and Yoon–Nelson models showed lower fitting performance. Because complete saturation was not reached, model-derived parameters were interpreted comparatively. Overall, the integrated PET-Fe-BDC composite-geotextile-amended soil system substantially delayed Pb(II) and Cd(II) breakthrough under continuous seepage, demonstrating its potential for groundwater-remediation barriers.