红黏土备样方法对路用指标的影响

Impact of Preparation Methods of Red Clay on Road Index

以贵州红黏土为研究对象,通过干土法和湿土法备样并进行试验,研究备样方法对红黏土的液塑限、击实与加州承载比指标的影响;结合SEM扫描电镜试验,基于温度变化对结合水和胶结物质的影响,分析了备样方法对路用指标的影响机理。结果表明:湿土法的液限与塑限分别高于干土法3.0%~6.0%与1.0%~6.0%,最佳含水率高于干土法2.0%~3.0%,最大干密度低于干土法0.03~0.08 g/cm^(3),CBR值高于干土法0.6%~1.1%,其差值约为湿土法的12.0%~25.0%。干土法烘干导致弱结合水丧失和胶结物质凝胶特性失效,是备样方法对其路用性能影响的根本原因。红黏土的路用指标适宜采用湿土法,可拓宽红黏土的应用范围。

Taking the rad clay in Guizhou as the research object,the effects of sample preparation methods on the liquid-plastic limit,the compaction and the California Bearing Ratio were studied through laboratory experiments by using water-reducing method and watering method respectively.Combined with SEM scanning electron microscope test,based on the influence of temperature change on bound water and cementitious substances,the influence mechanism of sample preparation methods on road index was analyzed.The results show that the liquid limit and plastic limit by using water-reducing method are higher than those by using watering method about3.0%~6.0%and 1.0%~6.0%respectively.The optimum moisture content is about 2.0%~3.0%higher than that by using watering method.The maximum dry density is lower than that by using watering method about0.03~0.08 g/cm^(3).The CBR value is about 0.6%~1.1%higher than that of watering method,and the difference is about 12.0%~25.0%of the water-reducing method.The loss of weak bound water and the gelling property of cementitious substance caused by drying are the fundamental reasons for the influence of the sample preparation methods on its road performance.The road index of red clay is suitable for water-reducing method,which can broaden the application range of red clay.