Solidification Performance and Mechanism of TSC Composite Soil Based on Microbially Induced Mineralization

Area of Science:

• Geotechnical Engineering
• Materials Science
• Environmental Engineering

Background:

• Fine-grained composite soils often exhibit poor engineering properties like low water stability and high plasticity.
• Existing stabilization methods may not fully address the complex challenges posed by unbalanced particle gradation.

Purpose of the Study:

• To develop a synergistic strategy for enhancing the engineering performance of titanium gypsum-clay (TSC) composite soils.
• To investigate the combined effects of particle structure regulation and microbially induced calcium carbonate precipitation (MICP) on soil properties.

Main Methods:

• Systematic single-factor blending tests to optimize the titanium slag (TS) to clay (C) ratio.
• Application of MICP treatment to the optimized composite soil.
• Analysis using X-ray diffraction (XRD) and scanning electron microscopy (SEM) to understand reinforcement mechanisms.

Main Results:

• An optimal TS:C ratio of 60:40 significantly improved soil gradation, reduced plasticity, and enhanced compaction and load-bearing capacity.
• MICP treatment markedly increased the water stability coefficient from 0.35 to 0.83.
• Microscopic analysis revealed calcite precipitation forming a cementation network, reducing porosity by approximately 32% and mitigating strength loss.

Conclusions:

• The synergistic strategy of particle structure regulation and MICP is highly effective for improving the water stability and structural integrity of fine-grained composite soils.
• This approach offers a sustainable solution for utilizing and improving challenging soil types in engineering applications.