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Early-age hydration characteristics of modified coal gasification slag-cement-aeolian sand paste backfill
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Highlights The hydration exothermic characteristics of MGCAPB by isothermal microcalorimetry. Hydration kinetic of MGCAPB was analysed by Krstulović-Dabić model. Mechanical properties of MGCAPB was investigated by UCS and elastic modulus. Microstructure of MGCAPB was studied by TG-DTG and SEM.
Abstract A clear understanding of the hydration characteristics of cemented paste backfill (CPB) is helpful to analyze the reasons for the defects of low strength, large deformation and high cost in the early curing period of CPB. This is conducive to realizing the sustainable utilization of solid waste. In this paper, the hydration exothermic characteristics of MGCAPB slurry was tested. Moreover, uniaxial compressive strength(UCS) tests were carried out on the MGCAPB with curing times of 3 and 28 d. In addition, microstructure tests such as TG-DTG and SEM were performed on the MGCAPB with curing time of 3d. The hydration exothermic characteristics of MGCAPB were emphatically studied, the hydration kinetic parameters of MGCAPB were analyzed exclusively by using Krstulović-Dabić model. In addition, the mechanical properties and microscopic characteristics of MGCAPB were studied. The results shows that the hydration kinetic process of MGCAPB slurry can be described by nucleation and crystal growth (NG), phase boundary reaction (I) and diffusion (D). All the formulations of MGCAPB went through the NG-I-D stage. The process of hydration reaction was controlled by NG at the initial hydration stage, and gradually changed to process I and process D with the increase of hydration degree. Compared to the Control group, The α1 of the MGCAPB activated by the activator was high, indicating that the NG process changed to the I process only when the hydration degree was high, which was related to the effective water-cement ratio of the slurry and nucleation effect. In addition, according to the requirement(3d ≥ 0.5 MPa and 28d ≥ 1.0 MPa) that CPB can provide good roof support in a typical underground mine. In this experiment, the mechanical propertiesof all formulations met the requirements, except for the 3d UCS of the Control group(0.37 MPa) and the C-C1(0.46 MPa). Finally, TG-DTG and SEM were used to analyze the microstructures of MGCAPB with activator type and dosage. The research results can provide a new approach for intensive and comprehensive utilization of solid waste resources.
Early-age hydration characteristics of modified coal gasification slag-cement-aeolian sand paste backfill
Graphical abstract Display Omitted
Highlights The hydration exothermic characteristics of MGCAPB by isothermal microcalorimetry. Hydration kinetic of MGCAPB was analysed by Krstulović-Dabić model. Mechanical properties of MGCAPB was investigated by UCS and elastic modulus. Microstructure of MGCAPB was studied by TG-DTG and SEM.
Abstract A clear understanding of the hydration characteristics of cemented paste backfill (CPB) is helpful to analyze the reasons for the defects of low strength, large deformation and high cost in the early curing period of CPB. This is conducive to realizing the sustainable utilization of solid waste. In this paper, the hydration exothermic characteristics of MGCAPB slurry was tested. Moreover, uniaxial compressive strength(UCS) tests were carried out on the MGCAPB with curing times of 3 and 28 d. In addition, microstructure tests such as TG-DTG and SEM were performed on the MGCAPB with curing time of 3d. The hydration exothermic characteristics of MGCAPB were emphatically studied, the hydration kinetic parameters of MGCAPB were analyzed exclusively by using Krstulović-Dabić model. In addition, the mechanical properties and microscopic characteristics of MGCAPB were studied. The results shows that the hydration kinetic process of MGCAPB slurry can be described by nucleation and crystal growth (NG), phase boundary reaction (I) and diffusion (D). All the formulations of MGCAPB went through the NG-I-D stage. The process of hydration reaction was controlled by NG at the initial hydration stage, and gradually changed to process I and process D with the increase of hydration degree. Compared to the Control group, The α1 of the MGCAPB activated by the activator was high, indicating that the NG process changed to the I process only when the hydration degree was high, which was related to the effective water-cement ratio of the slurry and nucleation effect. In addition, according to the requirement(3d ≥ 0.5 MPa and 28d ≥ 1.0 MPa) that CPB can provide good roof support in a typical underground mine. In this experiment, the mechanical propertiesof all formulations met the requirements, except for the 3d UCS of the Control group(0.37 MPa) and the C-C1(0.46 MPa). Finally, TG-DTG and SEM were used to analyze the microstructures of MGCAPB with activator type and dosage. The research results can provide a new approach for intensive and comprehensive utilization of solid waste resources.
Early-age hydration characteristics of modified coal gasification slag-cement-aeolian sand paste backfill
Xin, Jie (author) / Liu, Lang (author) / Jiang, Quan (author) / Yang, Pan (author) / Qu, Huisheng (author) / Xie, Geng (author)
2021-11-26
Article (Journal)
Electronic Resource
English
Coal chemical gasification slag and coal gangue backfill material and preparation method thereof
| European Patent Office | 2023