氧化镁复合膨胀剂对高性能混凝土变形特性的影响  

Deformation behavior of high performance concrete containing MgO composite expansive agent

作　　者：刘加平[1] 张守治[1] 田倩[1] 郭飞[1] 王育江[1] 

机构地区：[1]江苏省建筑科学研究院有限公司高性能土木工程材料国家重点实验室,南京210008

出　　处：《东南大学学报（自然科学版）》2010年第A02期150-154,共5页Journal of Southeast University：Natural Science Edition

基　　金：国家重点基础研究发展计划(973计划)资助项目(2010CB735801);"十二五"国家科技支撑计划资助项目(SQ2010BAJY1157)

摘　　要：从氧化镁复合膨胀剂对高性能混凝土安定性能和力学性能的影响规律出发,系统研究了该新型氧化镁复合膨胀剂在不同养护方式下对高性能混凝土变形特性的影响规律.结果表明:在确保安定性的前提下,氧化镁复合膨胀剂在高性能混凝土适宜掺量为不超过8%.内掺8%的氧化镁复合膨胀剂对高性能混凝土力学性能影响不大,但对高性能混凝土的变形特性有显著影响.在饱水养护条件下,氧化镁复合膨胀剂既具有较大的早期膨胀性能,又具有一定的持续微膨胀性能;在密封养护条件下,氧化镁复合膨胀剂的掺入能完全消除高性能混凝土的早期自收缩,产生自膨胀;在干燥养护条件下,氧化镁复合膨胀剂的掺入对高性能混凝土的干燥收缩也表现出明显的抑制效果,至120d测试龄期时干燥收缩的减缩率仍然高达50.2%.The effects of MgO composite expansive agent on deformation characteristics under various curing conditions are systematically investigated after taking into account of the impacts on the stability and mechanical properties of high-performance concrete.The results indicate that,on the premise of ensuring stability,appropriate dosage of MgO composite expansive agent for high performance concrete is less than 8%.When adding 8% of the MgO composite expansive agent,no negative effects on mechanical properties of high performance concrete is detected;however,the deformation properties are significantly influenced.On saturated water curing conditions,high performance-concrete with MgO composite expansive agent both expansive great performances in the early expansion and certain properties of continuous micro-expansion;on sealed-curing conditions,the early autogenous shrinkage of high-performance concrete can be completely eliminated by adding MgO composite expansive agent.On dry curing conditions,the drying shrinkage also decreases markedly.At the age of 120d,the shrinkage rate is up to 50.2%.

关 键 词：氧化镁复合膨胀剂 膨胀特性 自生体积变形 干燥收缩 高性能混凝土 

分 类 号：TU528[建筑科学—建筑技术科学]