Mix Ratio Optimization of Cemented Coal Gangue Backfill (CGB) Based on Response Surface Method

摘要

Central composite design (CCD) experiments were performed to investigate the effect of cement content, fine gangue rate and water reducer content on the rheological properties of fresh cemented coal gangue backfill (CGB) and the compressive strength of hardened slurry. The parameter of mixture proportion was optimized by Multi-criteria optimization analysis. The results show that the fresh CGB rheological property conforms to Bingham model, the yield stress of fresh slurry is influenced by the interaction of the three factors, and the plastic viscosity increases with cement content, fine gangue rate and water reducer content. The value of 28 days uniaxial compressive strength (UCS28) is proportional to cement content and water reducer content, while it is inversely proportional to fine gangue rate. The overall satisfaction of slurry rises significantly with the increase of water reducer content. However, it increases firstly and then decreases with the increase of cement content and fine gangue rate, and reaches a maximum at cement content of 210 kg/m(3) and fine gangue rate of 40%. The developed design method can provide scientific reference to reduce the accumulation of waste residues.