具有膨胀特性膏体充填材料的物理力学特性研究

Study on Physical and Mechanical Characteristics of Paste Filling Material with Swelling Properties

针对煤矿采空区膏体充填材料无法充分接顶的现状,运用X射线衍射仪(XRD)及X射线荧光光谱分析仪(XRF)对膨润土、煤矸石、粉煤灰等膏体充填材料进行化学物相分析,结合自制的膨胀测定仪器,分析检测不同膨润土掺入比的膏体材料膨胀率随时间的变化关系,并对不同养护龄期下的膏体试件进行力学性能测试与微观水化机理研究。结果表明:配比P04为最优配比,即胶结料∶膨润土∶煤矸石∶粉煤灰为1∶0.6∶3∶4,质量浓度为72%,28d单轴抗压强度为4.85 MPa,膨胀率为2.25%。P04膏体衍射谱图表明,不同龄期的水化产物各物质含量各不相同,在水化初期8h内即生成一定量的钙矾石,28d生成大量的C-S-H凝胶。

According to the the situation that paste filling material can not adjoin roof completely in coal goaf,the chemical phase of paste filling materials,such as bentonite,coal gangue and fly ash,was analyzed by X-Ray Diffraction(XRD)and X-Ray Fluorescence Spectrometer(XRF).Combined with the self-made expansion device,the variation relationship between expansion ratio of different bentonite mixing ratio and time was analyzed. Meanwhile,mechanical property tests and micro hydration mechanism researches for paste specimens under various curing ages were carried out.The results showed that the most optimized proportion was P04 when the ratio of cementing material,bentonite,coal gangue and fly ash was 1∶0.6∶3∶4,the mass concentration was 72%,the 28 days uniaxial compressive strength was 4.85 MPa and the expansion rate was 2.25%.The XRD map of P04 paste material showed that substance contents of hydration products in different curing ages were various.A certain amount of ettringite was produced in early hydration of 8hours and large of C-S-H gel was found in 28 days.