外掺轻烧氧化镁混凝土的长龄期自生体积变形研究  

Study on the long-term autogenous volume deformation of concrete admixed with light-burned magnesia

作　　者：周世华[1,2] 苏杰[1] 杨华全[1,2] 彭尚仕[1,2] 

机构地区：[1]长江水利委员会长江科学院,湖北武汉430010 [2]三峡地区地质灾害与生态环境湖北省协同创新中心,湖北宜昌443000

出　　处：《混凝土》2014年第12期73-75,共3页Concrete

基　　金：国家自然科学基金(51279017;51139001);"十二五"科技支撑(2011BAE27B01)

摘　　要：氧化镁具有延迟性膨胀特性已被工程界所认识并应用于补偿大体积混凝土的温降收缩，因此，保证氧化镁混凝土的长龄期体积稳定性是非常重要的。主要研究了外掺轻烧氧化镁混凝土自生体积变形的长期发展规律。研究结果表明，混凝土中轻烧氧化镁的膨胀开始时间在1~3d左右，终止时间随粉煤灰掺量的增加而延长；混凝土强度对氧化镁的膨胀变形起到了约束作用，水胶比越小，外掺氧化镁混凝土的后期体积膨胀变形越小；粉煤灰对混凝土中氧化镁的膨胀作用具有抑制效果，从长期发展规律来看，外掺轻烧氧化镁混凝土可通过调整粉煤灰掺量和氧化镁掺量来控制膨胀速率与膨胀量，以保证其长龄期体积稳定性。Magnesium oxide with delayed expansion has been known by in engineering circles and can be used for compensating mass concrete shrinkage for temperature fall and improve the crack resistance of concrete itself.The long-term development law of autogenous volume deformation of concrete admixed with light-burned magnesia was studied.The results show that the initial expanding time of the light-burned magnesia in concrete is about 1~3 d,and the stabilization expanding time extend along with the increase of fly ash content. The strength of concrete has a constraint effect on expansion deformation.The W/C ratio is smaller ,the expanding deformation at later ages is smaller.From the long-term development law of volume deformation,the concrete admixed with light-burned magnesia could be adjust-ed by the magnesium oxide content and the fly ash content to control the expansion rate and the expansion capacity.

关 键 词：轻烧氧化镁 自生体积变形 长龄期 大体积混凝土 

分 类 号：TU528.041[建筑科学—建筑技术科学]