Enhanced mechanical properties and durability of coal gangue reinforced cement-soil mixture for foundation treatments

High-speed railways with high load capacity and long-term performance have been developed by the aid of high-performance construction materials for foundation treatments. The mechanical properties and durability of new cement-soil mixture reinforced by local sourced waste coal gangue aggregate were investigated in this study. Extensive experiments were carried out to analyse the effects of coal gangue on compressive strength, elastic modulus, stress-strain curve and anti-corrosion of cement-soil mixture. The results show that incorporation of coal gangue significantly improve the strength, stiffness and anti-corrosion ability of cement-soil mixture. Strength improvements up to 81.8% was achieved, but the ductile failure model shited to brittle failure with more than 42% coal gangue reinforcements. Except for the declining segment of the stress-strain curve, the ascending segment of the stress-strain curve can be fitted by the existing models. From the microstructural characterization, coal gangue can reduce acid solution permeation compared to the soil. For the cemented soil with coal gangue, the mass-loss rates only reach 4–7% after 140 days acid solution immersion. Therefore, this new clean production of high-performance cement-soil mixture through waste coal gangue reinforcement has great potential for railway foundation treatments.