Study on the Performance of the Steel Slag Base Stabilized by Multiple Solid Waste Geopolymer

With the deepening of the concept of sustainable development, cement-stabilized macadam—a traditional road base material—faces increasing demand for improvement due to its high resource consumption, significant environmental pollution, and poor shrinkage performance. Steel slag, an important solid waste product of the steel industry, accumulates in large quantities, resulting in resource waste and environmental pollution. Conventional cement-stabilized steel slag base materials suffer from drawbacks such as high carbon emissions and poor volumetric stability. In this context, geopolymers emerge as an environmentally friendly alternative starting from the raw material level. This study proposes the use of three solid waste materials—fly ash, ground granulated blast furnace slag (GGBS), and red mud—in combination with an alkali activator to enhance the performance of geopolymer-stabilized steel slag as a road base material. These industrial solid wastes serve as cementitious materials replacing traditional cement, while steel slag is introduced as a substitute for natural aggregates. A series of laboratory tests, including compressive strength tests, splitting tensile tests, drying shrinkage tests, and freeze-thaw cycle tests, was conducted to comprehensively evaluate the pavement performance of the geopolymer-stabilized steel slag mixture. The aim is to achieve the dual objectives of solid waste recycling and the development of low-carbon road materials. The results indicate that the geopolymer-stabilized steel slag mixture meets the specifications required for road base materials. Geopolymers show promise as a replacement for cement, with steel slag serving as the base aggregate, forming a new type of green semi-rigid base material.