膨润土对泡沫膏体充填材料孔结构及强度的影响∗

摘要

通过添加膨润土成功制备了孔径分布均匀的泡沫膏体充填材料,利用 X 射线衍射仪和扫描电镜分析了膨润土掺加前后泡沫膏体充填材料的水化产物及孔隙结构,研究了膨润土掺量对泡沫膏体充填材料28 d 抗压强度的影响.结果表明,膨润土的掺加提高了气泡稳定性,有利于泡沫的引入,易于制备较低干密度的泡沫膏体充填材料,但膨润土对泡沫膏体充填材料水化产物的生成有一定抑制作用；在水料比为0．7~0．8时,掺加2．0％~4．0％(质量分数)膨润土可使微细孔含量明显增多,气孔孔径分布集中,比较均匀的孔隙结构改善了泡沫膏体充填材料的强度,28 d 抗压强度可达0．50~0．73 MPa,满足煤矿充填使用要求.%The hydration products and pore structure of foam paste backfill materials with or without bentonite was analyzed by X-ray diffraction(XRD)and scanning electron microscopy(SEM),the influence of the content of bentonite on 28 days compressive strength of foam paste backfill materials was studied.The results showed bentonite improved the stability of the bubbles,which was beneficial to the bubble introduction.As a result,it was easy to prepare foam paste backfill materials with low dry density.However,bentonite had a certain inhibi-tory effect on the generation of hydration products;with 2-4wt% bentonite,the content of microspore was sig-nificantly increased,and pore size distribution was concentrated.Because of relatively uniform pore structure, compressive strength of foam paste backfill materials had been improved,28 days compressive strength could reach 0.50-0.73 MPa,which could meet the operating requirement of coal backfill.