煤矿采空区充填用煤矸石泡沫混凝土发泡剂的研究

Research on foaming agent of coal gangue foam concrete for filling

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。

This paper intends to discuss and analyze the mechanism of foaming and foaming stabilization to increase the availability of the foaming agent of coal gangue foaming concrete for goaffilling. As a matter of fact,it is of great importance to refill the goaf left-over by the coal-mining to prevent the earth surface collapse or crack down. For the time being,there exist a few available filling methods,with the cementing filling and high-water quick-setting filling being the most common ones. However,in this paper we would like to introduce foam concrete to be used as the goaf-filling material for it is being light in weight and fine in fluidity. What is more,its high foaming stability may also account for its satisfactory function in preparing foam concrete with large coal gangue particles and low concentrated cement. In spite of this,it is still difficult to prepare foam concrete for goaf filling with commercially available foaming agents due to its low foaming stability. For this purpose,we have made an investigation of the effects of a foam stabilizer D on the viscosity of the foaming liquid,the foaming rate and the foaming stability. Mixing foam stabilizer（ D） with lauryl sodium sulfate（ SDS） water liquid to gain a new foaming agent（ KD- 1）. The foaming rate of KD- 1 is21. 3,the water bleeding start time is 7 min,the settlement distance after 90 min is 38 mm,and the KD- 1 has good compatibility with the early strength agents of the concrete. The coal gangue foam used for goaf filling with a bulk density between 800- 1 000 kg / m3 has been prepared with the maximum coal gangue particle size being 5 mm and up to 63 wt% coal gangue was added. The uniaxial compressive strength of the foam concrete with bulk density 800 kg / m3,900 kg/m3,1 000 kg/m3 is 0. 4 MPa,0. 63 MPa and 1. 75 MPa for 90-day,respectively.