偏高岭土对RAC性能增强及微观作用机理试验研究  

Experimental study on RAC performance enhancement and micro action mechanism of metakaolin

作　　者：李庆瑞[1] 徐晋[2] LI Qingrui;XU Jin(College of Civil Engineering,Xijing University,Xi′an 710123,China;College of Civil Engineering,Xi′an University of Architecture and Technology,Xi′an 710055,China)

机构地区：[1]西京学院土木工程学院,陕西西安710123 [2]西安建筑科技大学土木工程学院,陕西西安710055

出　　处：《混凝土》2021年第5期84-87,共4页Concrete

基　　金：国家自然科学基金(51178388);陕西省教育厅重点实验室科研计划项目(11JS059,12JS055)。

摘　　要：为了研究偏高岭土对RAC性能的影响,对6组54块不同偏高岭土取代率下的RAC进行了抗压、劈裂抗拉、抗折、脆性、强度作用机理、微观电镜(SEM)研究,研究结果表明:各偏高岭土取代率下,立方体抗压强度均高于基准组,且随着偏高岭土取代率的增加,立方体抗压强度大致呈现先增加后减小趋势;偏高岭土取代率大于15%时,RAC劈裂抗拉强度相比基准组有很大涨幅;偏高岭土取代率下,RAC抗折强度相比基准组分别提高了23.7%、34.2%、30.1%、46.5%、37.6%;偏高岭土取代率20%时,对于RAC脆性改善较为明显,同时此取代率下,K_S达到最大值,对于强度的提升表现出良好的效果;随着偏高岭土取代水泥量的增加,结构内部水化产物越来越多,生成了较多的凝胶物质,使得水泥石与骨料界面黏结力增强,孔隙变小,界面及整体结构趋于密实,有利于RAC力学性能的提高。In order to study the effect of metakaolin on the performance of RAC,it studies the compressive strength,splitting tensile strength,bending resistance,brittleness,strength mechanism and micro electron microscope(SEM)of RAC under six groups of 54 pieces of metakaolin with different replacement rates.The results show that the compressive strength of the cube under the replacement rates of metakaolin is higher than that of the reference group,and with the increase of replacement rates of metakaolin,the cube compressive strength increased first and then decreased.When the replacement rate of metakaolin was more than 15%,the tensile strength of RAC splitting increased greatly compared with the reference group.When the replacement rate of metakaolin was higher,the flexural strength of RAC increased by 23.7%,34.2%,30.1%,46.5%and 37.6%compared with the reference group.When the replacement rate of metakaolin was 20%,the brittleness of RAC was improved obviously,and at the same time,the KS was improved significantly with the increase of metakaolin replacing cement,there are more and more hydration products in the structure,and more gel materials are generated,which makes the interface adhesion between cement stone and aggregate increase,the pores become smaller,the interface and the overall structure tend to be dense,which is conducive to the improvement of RAC mechanical properties.

关 键 词：RAC 偏高岭土取代率 力学性能 压拉比 强度效率系数 SEM 

分 类 号：TU528.041[建筑科学—建筑技术科学]