From Mine Waste to Road Base: Cracking Resistance and Durability of Cement-Stabilized Crushed Stone Incorporating Lead–Zinc Mine Waste Rock Aggregate

To alleviate the shortage of high-quality natural aggregates and promote the sustainable utilization of mining waste rock, this study employed lead–zinc mine waste rock-derived aggregate to replace 50% of the coarse aggregate by mass in cement-stabilized crushed stone. A series of tests, including drying shrinkage, thermal shrinkage, freeze–thaw cycling, scouring, and sulfate attack, were conducted to investigate the cracking resistance and durability of the resulting mixtures. The effects of basalt fiber, low-alkali cement, and a sulfate-resistant agent were further evaluated. Although the waste rock aggregates exhibited relatively inferior particle morphology, they could be incorporated into cement-stabilized crushed stone through rational gradation design. Among the investigated fiber contents, the mixture containing 4‰ basalt fiber exhibited relatively favorable shrinkage, freeze–thaw, and scouring resistance. The sulfate-resistant agent reduced mass loss and strength degradation under the investigated sulfate wet–dry cycling conditions. In contrast, low-alkali cement showed limited effectiveness in improving shrinkage resistance and freeze–thaw durability. These results provide experimental evidence for the feasibility of using lead–zinc mine waste rock as a partial coarse aggregate replacement in road base materials under the investigated laboratory conditions.