Road performance and strength mechanism of aeolian sand subgrade solidified by full solid-waste cementitious materials

This is the authors' abstract. We don't add key points for this paper.

Addressing aeolian sand's subgrade inadequacies (poor gradation, low cohesion) and overcoming traditional cement's high carbon emissions and alkali activation's reliance on external strong alkalis, this study developed a full solid waste cementitious material (FSWCM). It comprises alkaline solid waste (calcium carbide residue, blast furnace slag), aluminosilicate solid waste (fly ash, silica fume), and sulfate solid waste (desulfurization gypsum) at a 4:3:2:3:2 mass ratio. The effects of FSWCM dosage (0%–40%) and compaction degree (94%–100%) on the mechanical properties of aeolian sand were investigated, with the solidification mechanism revealed via XRD, FTIR, and SEM-EDS. Results show maximum dry density first rises then falls with FSWCM content. Higher dosage and compaction significantly improve shear strength, resilient modulus, CBR, and UCS. At 40% dosage and 100% compaction: 28-day UCS reaches 6.88 MPa; resilient modulus and CBR increase by 1.98 and 1.53 times, respectively. FSWCM-amended specimens show better water stability (with increased CBR values after soaking), higher aeolian sand stiffness, and a shift from plastic to brittle failure. Modification strengthens linear correlations among UCS, resilient modulus, and CBR; UCS and moisture content follow an exponential composite relationship. Microstructural analyses reveal calcium silicate hydrate (C-(A)-S-H), AFt, and calcium carbonate crystals form, boosting subgrade strength and stability. In conclusion, FSWCM offers an effective, sustainable solution for aeolian sand subgrades, with potential in low-carbon infrastructure in desertified regions.