Properties of coal gangue grouting filling material modified by alkaline additives
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摘要: 针对煤矿开采引起的地层破坏与塌陷问题，将煤矸石作为矿用充填材料回填不仅可以实现煤矸石的规模化处理，也可实现采空区的绿色高效治理。本研究基于煤矸石这一主要原料，采用碱性添加剂改性以制备煤矸石注浆充填材料。从黏度、析水率、结石率、凝结时间及力学性能分析其充填性能，并以XRD、TG-DSC、FT-IR、SEM解析其微观性质。结果表明注浆充填材料通过生成C-S-H凝胶及C-(N)-A-S-H凝胶产生胶结性能。激发剂的增加可有效促进煤矸石的二次水化，增加凝胶产物的生成。当煤矸石掺量为70%，激发剂掺量为30%，水灰质量比为0.7时，注浆充填材料综合性能最好，但黏度较大，不利于长距离泵送。当煤矸石掺量为80%，激发剂掺量为20%，水灰质量比在1.0时，浆料具有较好的泵送性能，且体积稳定性和力学性能较好，可降低成本，实现绿色低碳充填。Abstract: According to the problems of geological damage and collapse caused by coal mining, using coal gangue as the main component of mining filling materials can not only achieve large-scale processing of coal gangue, but also achieve the green and efficient management of the goaf. Coal gangue is used as one of the main materials, and the grouting filling material based on coal gangue is prepared under the modification of alkaline additives. The filling performance was analyzed from viscosity, bleeding rate, stone rate, setting time, and mechanical properties of the material. And the microscopical properties of the material were analyzed by XRD, TG-DSC, FT-IR, and SEM. Results show that C-S-H gel and C-(N)-A-S-H gel were formed in the grouting filling material, which brings bonding properties. The increase of the activator can effectively promote the secondary hydration of coal gangue and increase the formation of gel products. The performance of the grouting filling material is good when the coal gangue content is 70%, the activator content is 30%, and the water-cement ratio is 0.7. But the material is not conducive to long-distance pumping due to its high viscosity. The pumping performance of the slurry is good when the coal gangue content is 80%, the activator ratio is 20%, and the water-cement ratio is 1.0. The material has good slurry stability and mechanical properties, which can also reduce costs and achieve green and low-carbon effects.
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Key words:
- coal gangue /
- grouting filling /
- slurry performance /
- microstructure
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表 2 煤矸石注浆充填材料的正交试验
实验 煤矸石 水灰质量比 激发剂 1 70 0.7 30 2 70 1.0 30 3 70 1.3 30 4 80 0.7 20 5 80 1.0 20 6 80 1.3 20 7 90 0.7 10 8 90 1.0 10 9 90 1.3 10 
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表 3 煤矸石注浆充填材料的析水率
实验 煤矸石 水灰质量比 激发剂 析水率/% 1 70 0.7 30 0 2 70 1.0 30 0.81 3 70 1.3 30 3.47 4 80 0.7 20 0 5 80 1.0 20 0.74 6 80 1.3 20 3.15 7 90 0.7 10 0 8 90 1.0 10 0.69 9 90 1.3 10 3.04
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表 5 煤矸石注浆充填材料的黏度
试验 煤矸石 水灰质量比 激发剂 黏度/ (mMPa·s) 1 70 0.7 30 3476 2 70 1.0 30 473.1 3 70 1.3 30 349.6 4 80 0.7 20 3921 5 80 1.0 20 555.4 6 80 1.3 20 365.8 7 90 0.7 10 3177 8 90 1.0 10 473.1 9 90 1.3 10 261.8
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表 6 煤矸石注浆充填材料黏度试验结果的极差分析
指标 煤矸石/% 水灰质量比 k1 1432.900 3524.677 k2 1614.067 500.533 k3 1303.967 325.733 R 310.100 3198.934
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表 7 煤矸石注浆充填材料初凝时间
试验 煤矸石/% 水灰质量比 激发剂/% 初凝时间/ min 1 70 0.7 30 320 2 70 1.0 30 475 3 70 1.3 30 549 4 80 0.7 20 273 5 80 1.0 20 455 6 80 1.3 20 615 7 90 0.7 10 246 8 90 1.0 10 490 9 90 1.3 10 818
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表 8 煤矸石注浆充填材料初凝时间的极差分析
指标 煤矸石/% 水灰质量比 k1 448.000 279.667 k2 447.667 473.333 k3 518.000 660.667 R 70.333 381.000
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表 9 煤矸石注浆充填材料在不同龄期下的抗折强度
试验 煤矸石/% 水灰质量比 激发剂/% 抗折强度/MPa 3 d 7 d 28 d 1 70 0.7 30 0 0.7 1.0 2 70 1.0 30 0 0.4 0.7 3 70 1.3 30 0 0.3 0.4 4 80 0.7 20 0 0.5 0.9 5 80 1.0 20 0 0.6 0.7 6 80 1.3 20 0 0.2 0.7 7 90 0.7 10 0 0.3 0.7 8 90 1.0 10 0 0 0.3 9 90 1.3 10 0 0 0.1
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表 10 煤矸石注浆充填材料抗折强度极差分析
7 d 28 d 指标 煤矸石/% 水灰质量比 指标 煤矸石/% 水灰质量比 k1 0.467 0.500 k1 0.700 0.867 k2 0.433 0.333 k2 0.767 0.567 k3 0.100 0.167 k3 0.367 0.400 R 0.367 0.333 R 0.400 0.467
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表 11 煤矸石注浆充填材料在不同龄期下的抗压强度
试验 煤矸石/% 水灰质量比 激发剂/% 抗折强度/MPa 3 d 7 d 28 d 1 70 0.7 30 0 3.0 3.7 2 70 1.0 30 0 2.2 2.5 3 70 1.3 30 0 0.6 1.1 4 80 0.7 20 0 2.5 3.3 5 80 1.0 20 0 0.5 0.6 6 80 1.3 20 0 0.3 0.5 7 90 0.7 10 0 0.3 0.6 8 90 1.0 10 0 0 0.2 9 90 1.3 10 0 0 0.1
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表 12 煤矸石注浆充填材料抗压强度的极差分析
7 d 28 d 指标 煤矸石/% 水灰质量比 指标 煤矸石/% 水灰质量比 k1 1.933 1.933 k1 2.433 2.533 k2 1.100 0.900 k2 1.467 1.100 k3 0.100 0.300 k3 0.300 0.567 R 1.833 1.633 R 2.133 1.966
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