约束条件下外掺MgO混凝土的强度与膨胀应力  

Strength and Expansive Stresses of Concrete with MgO-Type Expansive Agent under Restrain Conditions

作　　者：李延波[1,2] 邓敏[1,2] 莫立武[1,2] 唐明述[1,2] 

机构地区：[1]南京工业大学材料化学工程国家重点实验室,江苏南京210009 [2]南京工业大学材料科学与工程学院,江苏南京210009

出　　处：《建筑材料学报》2012年第4期446-450,共5页Journal of Building Materials

基　　金：国家重点基础研究发展计划(973计划)项目(2009CB623105)

摘　　要：研究了掺0%,5%,8%,12%(质量分数)MgO混凝土的自由膨胀、约束膨胀及其在约束条件下的抗压强度和膨胀应力.结果表明:混凝土的自由膨胀随着MgO掺量的增加而增大,560d龄期时,MgO掺量为0%,5%,8%和12%的混凝土其最大膨胀量分别为-33×10-6,90×10-6,230×10-6和320×10-6.MgO掺量相同时,三维约束试件强度>二维约束试件强度>自由试件强度.三维约束条件下,混凝土膨胀应力随MgO掺量的增加而增大;在三维方向上膨胀应力大小规律为pc,x>pc,z>pc,y;膨胀应力随养护龄期的延长而增加并在一定龄期内趋于稳定.Free expansion, three-direction expansion stresses and strength of concrete under restraints were investigated. Results indicate that free expansions of concrete with 0%,5%,8% and 12%（by mass） MgO are -33×10^-6,90×10^-6,230×10^- 6 and 320×10^-6 at 560 d. The strength of concrete with MgO restrained in three-dimension is higher than that restrained in two-dimension, the latter is higher than that of con crete unrestrained. Under the three-dimensional restraints, the expansive stresses of concrete increase with increase of MgO-type expansive agent. What is more, the specimen size has an obvious effect on the expansive stresses of concrete： Pc,x〉 Pc,x〉 Pc,y. With the increase of curing age, the expansive stresses tend to be stable in the experiment.

关 键 词：约束条件 MGO混凝土 膨胀 抗压强度 膨胀应力 

分 类 号：TU528[建筑科学—建筑技术科学]