胶结充填体内部微观结构演化及其长期强度模型试验  

Experiment on evolution of microstructures and long-term strength model of cemented backfill mass

作　　者：徐文彬[1] 潘卫东[1] 丁明龙[1] 

机构地区：[1]中国矿业大学(北京)资源与安全工程学院,北京100083

出　　处：《中南大学学报（自然科学版）》2015年第6期2333-2341,共9页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51004109);国家科技支撑计划项目(2009BAB48B02);中央高校基本科研业务费专项基金资助项目(2013QZ02)~~

摘　　要：通过开展不同灰砂质量比、料浆质量浓度和养护龄期条件下的胶结充填体内部微观结构演化及其强度模型试验,研究充填体内部水化反应产物的类型及形态对其强度发展规律的影响。试验结果表明:水化作用后的水化产物在充填体内部的赋存形态不尽相同,早期多以针状物质存在,通过团絮状、丝状产物相联结;随着龄期的增长,团絮状胶凝物质大量生成,水化产物黏结得较紧密,机械强度得到了进一步的增强,表面仍可以看到少量针状物,但大部分已被絮状物覆盖;90 d时,早期水化反应产生的针状物几乎不存在,更多是以成团状、块状或成片状物质形式存在,且团状物质与团状物质或块状物质间黏结相当密实。对比水化产物元素分析结果可以看出,其主要成分由O,Si,Ca,Al和Mg等元素构成,灰砂质量比越大、料浆质量分数越高,水化产物元素量越多。对不同条件下的充填体强度曲线进行拟合,得到了充填体强度增长规律:充填体的强度增长规律基本一致,增长曲线呈"S"型;强度增长过程可分为强度增长初始时期、强度快速增长时期以及强度增长平缓期;灰砂质量比、料浆质量浓度越高,充填体强度增长越快,增长曲线变陡。Tests on the evolution of microstructures and long-term strength model of cemented paste backfill under different cement-sand mass ratio, slurry mass concentration and ageing were conducted to study the effects of types and forms of hydration reaction production within backfill on the strength model. Experimental results show that the types and speciation vary with curing ageing. At the early ageing, the substance of hydration production mostly exist being needle-like, consolidated by cotton-shaped and thread matters. As the curing time goes on, floccules mass is generated, and the hydration production bond gets closer together, resulting in the further increase of backfill strength. The needle-like substances exist, which are mostly covered with cotton-shaped matters. At the time of 90 d, the hydration production generated at the first stage rarely appears, are instead of the cotton-shaped matters, bonding densely. Elemental analysis by means of energy dispersive spectrometer （EDS） shows that the components produced by hydration are mostly consist of O, Si, Ca, Al and Mg element, and the number of elements increase directly as cement-sand mass ratio and slurry mass fraction. The increasing curves of long-term strength of backfill in the different conditions are gained and it shows that the increasing laws of backfill strength are unanimous, in accordance with a type of＂S＂ curve. The growth process can be divided into three parts： period of initial growth, period of rapid growth and smooth growth, respectively. The curves of strength increase in direct proportion to cement-sand mass ratio and slurry concentration.

关 键 词：胶结充填体 水化产物 微观结构 长期强度 

分 类 号：TU44[建筑科学—岩土工程]