Research on the mechanical properties and modification mechanism of loess treated by consolid system

The modification of loess in geotechnical engineering is critical for construction quality and preventing water erosion and disintegration. An urgent need for a modification technology that features lower content of conventional modifying agents, environmental friendliness, and excellent water stability. Traditional modification methods using lime and cement have limitations: they do not sufficiently improve water stability, cause brittle cracking at high dosages, and have poor environmental performance. The consolid system, a newer stabilization technology, uses low dosages, achieves high stabilization efficiency, and provides superior water stability. However, its effects on mechanical strength and water stability in loess areas need more systematic verification. In this study, modified loess using the consolid system was selected as the research object. Laboratory tests—including unconfined compressive strength (UCS), water stability coefficient, disintegration, and permeability—investigated the effects of stabilizer dosage and curing time on the strength, deformation, anti-disintegration, and permeability of loess. Linear models related the ultimate deformation modulus, average deformation modulus, and UCS. The mechanism of micro structural modification was analyzed using scanning electron microscopy (SEM). Test results reveal that loess treated with the consolid system boasts superior ecological compatibility compared with loess stabilized by high dosages of lime or cement. The optimal stabilizer dosage determined in this test is 3%, which halves raw material consumption versus the 6% dosage of lime or cement widely adopted in engineering projects, cutting down building material usage and carbon emissions. Meanwhile, its unconfined compressive strength (UCS) is 14.58%–42.89% higher than that of loess modified with 6% lime at all curing ages, yet 68.75%–78.12% lower than that of loess stabilized with 6% cement. Linear models were established to correlate the ultimate deformation modulus, average deformation modulus and UCS, with the fitting of ultimate deformation modulus versus UCS reaching a coefficient of determination R 2 of 0.9941. SEM quantitative analysis demonstrates that the consolid system effectively optimizes the pore structure: as the stabilizer dosage increases, large pores are filled and split into smaller pores, with the total pore area reduced by up to 75.5% at 4% dosage; this microstructural densification is the intrinsic cause for the improvement of macro-mechanical strength and the decrease of permeability coefficient. These findings offer important reference value for geotechnical engineering reinforcement, municipal road construction, and anti-seepage in soil and water conservation projects in loess regions.