高温下水泥基注材料性能试验研究

针对近年来不断出现的高地温条件下注浆堵水加固问题,在室内模拟高温环境,测试减水剂比例一定时,不同水灰比和膨润土掺量的浆液在不同温度下的凝结时间、黏度、析水率和抗压强度。结果表明:温度升高和膨润土掺量增加都使浆液凝结时间缩短、析水率降低,并使水灰比0.8的浆液黏度呈升高趋势,但对1.0和1.2的较高水灰比浆液影响不大;在20 ℃和40 ℃下,浆液随温度升高和龄期增长,结石体抗压强度不断增大,而在60 ℃和80 ℃的较高温度下,后期结石体强度会降低,且掺加膨润土会进一步降低强度。综合考虑浆液各方面性能,认为水灰比0.8时,在低于40 ℃环境下,膨润土掺量为6%较好,温度升高,则掺量为3%比较适宜;对于水灰比1.0和1.2的浆液,膨润土掺量为9%较为合适。

Study on Properties of Cement-based Grouting Material in High Temperature

In view of the emerging issues of grouting in geothermal field recently, the main properties of cement grout mixed with bentonite and water reducing agent were researched through simulate high geothermal environment in the laboratory. The properties including setting time, viscosity, syneresis ratio and compressive strength of the grout with different water-cement ratios, different proportions of bentonite and certain proportion of water reducing agent, were tested in different temperatures. According to the study, with the temperature and the content of bentonite increasing the sitting time and the syneresis ratio reduce, and the viscosity of grout with water-cement ratio of 0.8 increases gradually, nevertheless, the viscosity of grout with water-cement ratios of 1.0 and 1.2 changes little. At low temperature of 20℃ and 40℃, the compressive strength improves with the temperature and the curing age increasing, while the long-term compressive strength decreases at high temperature of 60℃ and 80℃, and bentonite can reduce the compressive strength further. For the grout with water-cement ratio of 0.8, the appropriate content of bentonite is 6% under the of temperature 40℃, and 3% as the temperature rises. For the grout with water-cement ratio of 1.0 and 1.2, the suitable content of bentonite is 6%.