高庙子膨润土热膨胀特性试验研究

采用DIL806热膨胀仪,通过室内试验系统研究了不同影响因素对高庙子压实膨润土样品热膨胀性能的影响,获得了膨润土样品热膨胀系数随干密度、升温速率、含水率和环境气氛等条件的变化规律。试验结果表明:膨润土样品的热膨胀系数随着干密度的增大而增大;样品热膨胀系数随初始含水率的升高而降低;高含水率的膨润土样品,其热膨胀系数随升温速率的升高而增大,含水率为0的试验样品其热膨胀系数随升温速率的升高略有下降;对于同一干密度和含水率的试验样品,空气氛围环境下样品的热膨胀系数要高于氩气氛围环境下的热膨胀系数。研究成果对分析膨润土的热膨胀性能,评价高放废物处置缓冲材料的长期稳定性具有一定的参考依据。

Experimental study on thermal expansion properties of GMZ bentonite

Laboratory tests are conducted on the compacted Gaomiaozi(GMZ) bentonite by using the DIL 806 thermal dilatometer.The influences of different factors on the thermal expansion properties of the bentonite are systematically analyzed.The thermal expansion coefficient of the bentonite is obtained with the dry density,the heating rate,the water content and the atmosphere environment.The experimental results show that the coefficient of thermal expansion increases with the dry density of the bentonite.The coefficient of thermal expansion decreases with the increase of the initial water content.The coefficient of thermal expansion increases with the increase of the heating rate for the samples with high water content,and the coefficient of thermal expansion decreases with the increase of the heating rate for the drying bentonite.Under the same dry density and water content of the samples,the coefficient of thermal expansion is higher in the air environment than that in the Ar gas environment.The research results have certain reference for analyzing the thermal expansion properties of the bentonite and evaluating the long-term stability of buffer materials for high-level radioactive waste disposal.