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为防止地表沉陷,煤矿采空区需要充填,目前采用的充填方法为胶结充填、高水速凝充填等。泡沫混凝土具有质轻、流动性好的特点,可作煤矿采空区的充填材料。制备低水泥用量、含粗颗粒煤矸石的泡沫混凝土对发泡剂的泡沫稳定性要求较高,目前市售的发泡剂难以满足要求。在探讨发泡剂发泡、稳泡原理的基础上,研究了稳泡剂(D)的加入量对发泡液黏度、发泡倍率和泡沫稳定性的影响,以D与十二烷基硫酸钠(SDS)复配,研制出了高泡沫稳定性的发泡剂KD-1,该发泡剂的发泡倍率为21.3,开始泌水时间为7 min,90 min后沉降距为38 mm,并且考察了KD-1与混凝土早强剂的相容性。用此发泡剂制备出了最大粒径为5 mm、煤矸石掺量为63%(质量分数)、体积密度分别为800 kg/m3、900 kg/m3和1000 kg/m3的煤矸石泡沫混凝土,其90 d单轴抗压强度分别为0.4 MPa、0.63 MPa和1.75 MPa。
In order to prevent surface subsidence, the coal mined area needs to be filled. Currently, the filling method used is cement filling and high-speed filling. Foamed concrete has the characteristics of light weight and good fluidity, and can be used as the filling material in the goaf of coal mines. The preparation of low cement content, with coarse particles of coal gangue foam foam on the foam stability requirements are higher, the current commercially available blowing agent is difficult to meet the requirements. Based on the principle of foam blowing and foam stabilization, the effects of the amount of foam stabilizer (D) on the viscosity, expansion ratio and foam stability of foaming liquid were studied. The effects of D and dodecyl sulfate Sodium dodecyl sulfate (SDS) complex to develop a high foam stability foaming agent KD-1, the foaming agent foaming ratio was 21.3, the beginning of the bleeding time of 7 min, 90 min after the settlement distance of 38 mm, The compatibility of KD-1 with concrete early strength agent was also investigated. With this foaming agent, the gangue foam concrete with the maximum particle size of 5 mm and the gangue content of 63% (mass fraction) and the bulk density of 800 kg / m3, 900 kg / m3 and 1000 kg / m3 were prepared respectively The 90-day uniaxial compressive strength is 0.4 MPa, 0.63 MPa and 1.75 MPa, respectively.