不同粒径组合对煤矸石基充填材料性能的影响

为解决胶结充填成本高、煤矸石和低品质粉煤灰等固废堆存占用大量土地及污染环境等问题,在充分利用煤矿固体废弃物、满足工程实际需求的前提下,制备了煤矸石基充填材料。根据不同胶凝材料的水化特性,研究了高活性辅助胶凝材料和低活性辅助胶凝材料的颗粒级配。通过组分筛选、配比优化、性能测试分析,获得了材料抗压强度、泌水率和流动度3项性能指标;利用XRD、SEM和压汞研究了不同粒径组合对充填材料性能的影响机理。研究表明:水泥熟料30%、煤矸石40%、粉煤灰20%、脱硫石膏10%为最优配比,此时早期强度发展较快,3 d强度达到0.83 MPa,后期强度最高,28 d强度达到9.92 MPa;煤矸石粒径变化对材料性能起主要作用,粉煤灰和脱硫石膏粒径变化起次要作用,并且存在最优的粒径组合,即煤矸石粒径0.075~0.106 mm、粉煤灰和脱硫石膏粒径0.053~0.075 mm的组合性能最优,材料的3 d抗压强度为0.78 MPa,28 d抗压强度达到12.1 MPa,流动度大于320mm,泌水率低。

Influence of Different Grain Size Combination on Gangue-based Filling Material

In order to overcome shortcoming of high cost of cementing and filling,and solve the problems of large landoccupied by solid waste such as gangue and low-quality fly ash,and environmental pollution,on the premise of making full useof the solid waste of local coal mining enterprises and meeting the actual needs of the project,gangue-based filling materialwere prepared.According to the hydration characteristics of different cementitious materials,the granule gradation of high ac-tivity auxiliary cementitious materials and low activity auxiliary cementitious materials was optimized.The macroscopic proper-ties such as compressive strength,fluidity and bleeding rate were obtained through the experiments of component selection,proportion optimization and mechanical property test and analysis.The influence mechanism of particle size combination onfilling material properties was studied by XRD,SEM and mercury injection.The study results show that cement clinker 30%,coal gangue 40%,fly ash 20% and desulphurization gypsum 10% were the optimal proportions,the strength developed rapidlyin the early stage,the 3 d compressive strength of the material is 0.83 MPa,and reached the highest in the later stage,the 28 dcompressive strength of the material is 9.92 MPa.The change of coal gangue particle size plays a major role in the materialproperties,while the change of fly ash and desulfurization gypsum particle size plays a secondary role,and there is an optimalcombination of particle size.When the grain size of gangue is from 0.075 mm to 0.106 mm and the grain size of fly ash and de-sulfurized gypsum is from 0.053 mm to 0.075 mm,the 3 d compressive strength of the material is 0.78 MPa,the 28 d compres-sive strength of the material is 12.1 MPa,the fluidity is over than 320 mm and the bleeding rate is low.