长龄期MgO混凝土自生体积变形与水泥基材料压蒸膨胀变形的关联性  

Relationship between autogenous volume deformation of long-age MgO-mixed concrete and autoclave-treated expansive deformation of cement-based materials

作　　者：陈昌礼[1] 陈荣妃[1] 颜少连 雷平[3] 李维维[1] 

机构地区：[1]贵州师范大学材料与建筑工程学院,贵州贵阳550025 [2]贵州省水利科学研究院,贵州贵阳550002 [3]贵州师范大学分析测试中心,贵州贵阳550001

出　　处：《水利水电科技进展》2018年第2期90-94,共5页Advances in Science and Technology of Water Resources

基　　金：国家自然科学基金(51269003;50969002);贵州省工业攻关项目(黔科合GZ字[2015]3025)

摘　　要：针对水利水电工程挡水坝常用的三级配粉煤灰混凝土,采用压蒸试验、自生体积变形观测、压汞分析、电镜扫描、X射线能谱等方法,对水泥砂浆、一级配混凝土的压蒸膨胀变形与龄期长达6 a的三级配外掺MgO混凝土自生体积变形的关联性进行了研究。结果表明:外掺MgO混凝土的自生体积膨胀变形与水泥砂浆、一级配混凝土的压蒸膨胀变形没有关联性。现行以水泥砂浆试件或一级配混凝土试件的压蒸膨胀变形曲线拐点或压蒸膨胀率为0.5%确定的坝体混凝土的MgO极限掺量,虽能够保障混凝土大坝安全运行,但未能反映外掺MgO混凝土膨胀变形的实际情况。Relationship between the autoclave-treated expansibility of cement mortar, one-graded concrete and the autogenous volume deformation of three-graded MgO-mixed concrete at six-year age for the three-graded fly ash concrete commonly used in water retaining dams of water conservancy and hydropower engineering were studied based on the methods such as autoclave-treated test, autogenous volume deformation observation, mercury intrusion porosimetry, scanning electron microscopy,energy-dispersive X-ray spectroscopy and so on. The results indicate that there is no relevance between the autoclave-treated expansibility and the autogenous volume deformation. The current standard to determine the limit MgO content in dam concrete is based on the inflection point of the autoclave-treated expansibility curve or the autoclave-treated expansion ratio at 0. 5% of cement mortar and one-grade concrete samples. This standard can ensure the safety operation of a concrete dam but the actual expansive deformation of MgO-mixed concrete cannot be reflected.

关 键 词：氧化镁混凝土 自生体积变形 压蒸膨胀变形 长龄期 关联性 

分 类 号：TV431[水利工程—水工结构工程]