采空区大掺量粉煤灰无机固化泡沫制备及特性研究

煤矿采空区漏风是引发煤火灾害的重要原因，传统充填堵漏材料易干裂，流动性差，成本高，因此研发出有效充填封堵漏风通道的新型材料十分必要。通过单因素变量法，以材料流动度、初凝时间、抗压强度为指标进行配比优选，研发出大掺量粉煤灰无机固化泡沫充填堵漏新材料。同时，利用红外光谱、X射线衍射仪、扫描电镜表征材料的水化过程。结果表明∶基于泡沫均匀度、发泡倍数、半衰期及析水率等参数，优选出十二烷基硫酸钠(SDS)∶辛癸基葡糖苷(APG)=1∶1，黄原胶(XG)∶瓜尔胶(GG)=1∶1的水基泡沫。研发的大掺量粉煤灰无机固化泡沫，其初凝时间与粉煤灰掺量、水灰比、泡沫掺量成正比；流动度与水灰比成正比，与粉煤灰掺量成反比，随泡沫掺量增加先上升后缓慢降低；抗压强度随粉煤灰掺量增加呈先增加后减小趋势，与水灰比和泡沫掺量呈反比关系。综合评价指标确定粉煤灰掺量为60%、水灰比为0.6、泡沫与复合浆液体积比为1∶1时，材料流动度好，为15.9 cm，初凝时间适中，为5 h，抗压强度高，28 d达到1.5 MPa。该材料的水化产物是钙矾石(AFT)以及C-S-H凝胶，由水泥先发生水化反应生成Ca(OH)2，后与粉煤灰反应生...

Preparation and characteristics of inorganic curing foam with large-volume fly ash in goaf

Air leakage in the goaf of coal mine is an important cause of coal fire disaster. The traditional filling and plugging materials are easy to crack, with poor fluidity and high cost. Therefore, it is necessary to develop new materials for effective filling and plugging of the air leakage channels. Herein, the new filling and plugging material of inorganic curing foam with large-volume fly ash was developed by optimizing the mix ratio based on material fluidity, initial setting time and compressive strength using the single factor variable method. Meanwhile, the material hydration process was characterized by the infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The results show that the water based foam with sodium dodecyl sulfate (SDS)∶decyl glucoside (APG) of 1∶1 and xanthan gum (XG)∶guar gum (GG) of 1∶1 is selected based on the foam uniformity, foaming multiple, half-life and water separation rate. The initial setting time of the inorganic curing foam with large-volume fly ash is proportional to the amount of fly ash, water cement ratio and foam content. The fluidity is proportional to the water cement ratio water and iversely propotional to the amount of tlyash content based on the fluidity decreases with the increasing of fly ash content, and increases first and then decreases slowly with the increasing of foam content. The compressive strength of inorganic curing foam with large-volume fly ash increases first and then decreases with the increasing of fly ash content, but it is inversely proportional to the water cement ratio and foam content. According to the comprehensive evaluation indexes, the material fluidity is good at 15.9 cm, the initial setting time is moderate at 5 h, and the compressive strength is great, reaching 1.5 MPa at 28 d when the fly ash content was 60%, the water-ash ratio is 0.6, and the volume ratio of foam to composite slurry is 1:1. The hydration products of the material include ettringite (AFT) and C－S－H gel. The hydration reaction of cement first generates Ca(OH)₂, and then the Ca(OH)₂ reacts with fly ash to generate AFT and C－S－H gel, thereby improving the compressive strength of inorganic curing foam with high-volume fly ash, which is capable of satisfying the requirements leakage blocking in goaf.