Experimental Study on Application of MICP Modified Coal Gangue in Cement Stabilized Material
In order to solve the problems of coal gangue with low strength,high water absorption and easy disintegration,the microbial induced carbonate precipitation(MICP)technology is used to strengthen and modify coal gangue.Through testing the apparent densities,water absorptions,crushing values and ultrasonic mass loss rate,and combining with the microscopic characterization of SEM,EDS and XRD,the effects of microbial mineralization time,concentration of bacteria solution and particle size of coal gangue on the performance of MICP modified coal gangue are studied,and the mechanism of MICP modifying coal gangue is revealed.The MICP modified coal gangue is applied to cement stabilized materials,and the properties of cement stabilized materials of MICP modified coal gangue and ordinary coal gangue are compared by testing unconfined compressive strength,splitting strength and compression modulus of resilience.The result shows that the MICP technology can improve the physical and mechanical properties of coal gangue.The larger the particle size of coal gangue are,the more obvious the MICP enhanced and modified effect are.Under the conditions that the OD600(absorbance value of solution at 600 nm wavelength)value of bacterial solution is 0.8 and biomineralization time is 7 d,the apparent density of MICP modified coal gangue increases by 14.66%,the water absorption rate decreases by 40.94%,and the crushing value decreases by 7.93%compared with ordinary coal gangue.The biological CaCO3 coated on the surface of coal gangue after MICP modification are calcite,which improve the performances of coal gangue,such as increasing the apparent density of coal gangue,decreasing the water absorption and crushing value and adding strength.Compared with the ordinary coal gangue,the optimum water content of cement stabilized materials of MICP modified coal gangue is decreases by 17.3%,and the maximum dry density increases by 7.9%.The unconfined compressive strength,indirect tensile strength and compression modulus of resilience of cement stabilized materials of MICP modified coal gangue are significantly higher than those of ordinary coal gangue.The cement stabilized MICP modified coal gangue shows higher strength,better crack resistance and deformation resistance.
NETL
NSTL
万方数据
