不同龄期下偏高岭土与煤矸石改性水泥砂浆性能研究  

Modified Cement Mortar with Metakaolin and Coal Gangue at Different Ages

作　　者：李龙吉 LI Longji(China Railway Construction Urban Construction Transportation Development Co.,Ltd.,Suzhou,Jiangsu 215000,China)

机构地区：[1]中铁建城建交通发展有限公司,江苏苏州215000

出　　处：《施工技术（中英文）》2024年第18期141-146,共6页Construction Technology

基　　金：江苏省建设系统科技项目(2023ZD038)。

摘　　要：在当前“双碳”背景下,对水泥砂浆中偏高岭土和煤矸石等替代材料的改性研究,可有效降低传统水泥砂浆碳排放量,减少对环境不良影响。通过偏高岭土、煤矸石取代5%,10%,15%,20%,30%的水泥制备胶砂试件,研究试件在不同掺量下随龄期变化其抗压强度、火山灰活性指数、抗拉强度、硫酸钠侵蚀后强度及电阻率的影响。结果如下:偏高岭土掺量为20%时抗压强度提高最大,煤矸石掺量为30%时抗压强度降低最大,试件抗压强度随龄期增加而提高;随着龄期增加,火山灰活性指数随偏高岭土、煤矸石掺量提高呈下降趋势;掺偏高岭土会提高试件的抗拉强度,而掺煤矸石试件的抗拉强度则先降低后提高,偏高岭土掺量为15%,煤矸石掺量为10%,对抗拉强度的提高最大;试件侵蚀后强度随偏高岭土掺量增加而增加,掺煤矸石则相反,试件侵蚀1次以内时强度较大,而在2~4次侵蚀时强度较小;掺偏高岭土和煤矸石后,试件的电阻率随龄期增加大致呈增大趋势,偏高岭土掺量为20%时较大,而掺加煤矸石对电阻率影响较小。Under carbon peaking and carbon neutrality background,the research on the modification of alternative materials such as kaolin and coal gangue in cement mortar can effectively reduce the carbon emissions of traditional cement mortar and minimize its adverse impact on the environment.Using metakaolin and coal gangue as substitutes for 5%,10%,15%,20%,and 30%cement to prepare sand specimens,this paper investigates the effects of different dosages on compressive strength,volcanic ash activity index,tensile strength,strength after sodium sulfate erosion,and electrical resistivity over time.The results are as follows:When the content of metakaolin is 20%,the compressive strength increases the most,and when the content of coal gangue is 30%,the compressive strength decreases the most.The compressive strength of the specimens increases with age;As the age increases,the activity index of volcanic ash tends to decrease with the increase of metakaolin and coal gangue content;The addition of metakaolin will increase the tensile strength of the specimen,while the tensile strength of the specimen mixed with coal gangue will firstly decrease and then increase.The maximum increase in tensile strength is achieved when the content of metakaolin is 15% and the content of coal gangue is 10%;The strength of the specimen after erosion increases with the increase of metakaolin content,while the opposite is true when coal gangue is added.The strength of the specimen is higher when the erosion frequency is less than one time,but lower when the erosion frequency is 2~4 times;After adding metakaolin and coal gangue,the electrical resistivity of the specimens generally shows an increasing trend with age.When the content of metakaolin is 20%,it is larger,while the addition of coal gangue has a smaller impact on the electrical resistivity.

关 键 词：偏高岭土 煤矸石 水泥砂浆 龄期 抗压强度 电阻率 

分 类 号：TU528[建筑科学—建筑技术科学]