Sustainable valorization of tailings and crushed stone wastes for novel high early-strength road-building material (HERM): Performance optimization, micro-mechanism, and field implementation

Abstract

The efficient reuse of gold mine tailings and crushed stone waste is a critical step toward sustainable mining practices. In this study, a novel high early-strength road-building material (HERM), comprising gold mine tailings, crushed stone, and cementitious materials derived from solid waste, is formulated for mine roadway pavements. A systematic investigation is conducted into the effects of varying compositions on the uniaxial compressive and flexural strengths (UCS and UFS) of the HERM, with the formulation optimization carried out using response surface methodology (RSM). The optimal mix design is determined with a water–binder ratio (W:B) of 0.288, a binder–aggregate ratio (B:A) of 1:1.290, and a tailings–crushed stone ratio (T:C) of 0.596. At just one day of curing, the optimized HERM achieves a UCS of 46.196 MPa and a UFS of 13.800 MPa, which confirm its excellent early strength performance. The strength mechanism is further elucidated by XRD, SEM-EDS, FTIR, and TG-DTG analyses, which reveals that early strength development is primarily attributed to the formation of AFt gels, along with C–S–H and Ca(OH)₂. An in-situ road construction trial is successfully executed at the Sizhuang Branch Mine, where the material enables the restoration of full pedestrian and vehicle traffic within 24 h of placement. These results highlight the practical viability of the proposed HERM and its value in promoting low-carbon, resource-efficient mining infrastructure.