Research on the stabilization of coal gangue materials is gaining momentum as environmental concerns and resource shortages intertwine with infrastructure development. A recent study investigates the properties of rubber powder slag-based polymer stabilized coal gangue materials, aiming to address several pressing issues, including high energy consumption associated with cement production, pollution from coal gangue, and the diminishing availability of aggregate resources for road construction.
China's rapid economic growth has led to extensive infrastructure projects, resulting in heightened demands on the cement industry. With cement production contributing approximately 5-7% to global greenhouse gas emissions and consuming substantial energy—around 113.5 kg of coal equivalent per ton of cement—researchers are increasingly focusing on eco-friendly alternatives. Geopolymers, made from industrial waste like fly ash and slag, offer one such sustainable solution.
This study particularly examines the effects of geopolymer content and the substitution rates of coal gangue on the mechanical and durability properties of the resulting materials, utilizing rubber powder as a stabilizing element. By replacing conventional aggregates with coal gangue—waste produced during coal mining—the study also seeks to mitigate the environmental impact of accumulated waste materials.
The mechanical performance of the geopolymer stabilized coal gangue was assessed through unconfined compressive strength and indirect tensile strength tests. The results indicated significant improvements when rubber powder was incorporated at optimal levels. When the rubber powder content was adjusted to around 1.2%, the drying shrinkage coefficient was reduced by 12.1%, showing the material's enhanced stability under drying conditions.
Conversely, higher concentrations of coal gangue led to decreased mechanical properties and frost resistance, stressing the importance of finding the right balance. It was also observed how the inclusion of rubber powder impacts the tensile properties negatively, which signifies the complexity of integrating flexible and rigid materials.
The research emphasizes the importance of continuous monitoring of the microstructure of the materials to gauge the effects of rubber powder and geopolymer interaction, particularly through the use of scanning electron microscopy. The findings suggest intriguing connections between the polymerization reactions and the mechanical behavior of the stabilized coal gangue mixture, highlighting the potential for future developments in infrastructure materials.
The exploration of rubber powder as part of the stabilization process not only helps to improve shrinkage performance, but also offers insights for recycling materials traditionally viewed as waste. This study reaffirms the relevance of geopolymers and rubber waste in advancing sustainable practices within the construction industry, making strides toward mitigating the environmental footprint of infrastructure developments.
With promising results, the research paves the way toward enhancing the durability and performance of road materials, pointing to the future possibilities of utilizing eco-friendly alternatives effectively. Continued exploration and application may well redefine standards and practices concerning the materials we use to build and sustain our infrastructures.