Research on the properties of polymer stabilized coal gangue materials in rubber powder slag base

In order to solve the problems of high energy consumption in cement production, environmental pollution by coal gangue, shortage of aggregate resources in road engineering, and improvement of shrinkage performance of semi-rigid base materials, the properties of rubber powder slag-based polymer stabilized coal gangue materials were studied. On the basis of raw material tests, the mechanical properties and durability of slag-based geopolymer stabilized materials with different geopolymer content and coal gangue substitution rate were studied. The unconfined compressive strength, indirect tensile strength, compressive rebound modulus, freeze-thaw and dry shrinkage tests of geopolymer stabilized crushed stone/coal gangue (GSS/GSG) mixtures with different rubber powder contents were carried out. The microstructure of geopolymer stabilized coal gangue mixture was analyzed by scanning electron microscopy and energy spectrum analysis. The results show that with the increase of geopolymer content, the compressive strength, indirect tensile strength and frost resistance of GSS continue to increase, but its drying shrinkage performance will be adversely affected. When coal gangue replaces natural gravel, its performance in all aspects has decreased, and the mechanical properties and frost resistance have decreased significantly. The incorporation of rubber powder will slightly reduce the mechanical properties of geopolymer stabilized coal gangue material, but can effectively improve its drying shrinkage performance. The optimum content of rubber powder is 1.2%, and the dry shrinkage coefficient is reduced by 12.1%. The bonding effect of C-S-H generated by slag can promote the formation of N-A-S-H gel from fly ash. The rubber powder can stabilize the pore of the coal gangue material and the energy absorption of the rubber powder by filling the geopolymer, so as to achieve the purpose of stabilizing the shrinkage performance and compressive resilient modulus of the coal gangue material by the geopolymer.