(2545)--养护环境对掺有氧化镁膨胀剂的应变_省略_化水泥基复合材料裂缝自愈.pdf

养护环境对掺有氧化镁膨胀剂的应变硬化水泥基复合材料 裂缝自愈合的影响 摘 要：用四点弯曲试验对掺有氧化镁膨胀剂(MEA) 的应变硬化水泥基复合材料(SHCC)试件(SHCC-MEA)加载诱导产生裂 缝，通过在不同养护时间测量其裂缝宽度以及毛细吸水量，研究了干燥(RH 50%)、水雾(RH 95%)、水(Tap water) 以及饱和氢 氧化钙溶液(Sat. Ca(OH)2) 4 种养护环境对其裂缝自愈合的影响，并通过电子显微镜和能谱仪(SEM-EDS)对愈合产物进行微观 分析。结果表明，氧化镁膨胀剂的加入有效提高了SHCC 裂缝愈合能力，在水雾环境下有明显效果；水分是裂缝自愈合过程 中必不可少的条件，即使掺有氧化镁膨胀剂，干燥环境下的愈合效果依然很差；相比于对照组，饱和氢氧化钙溶液环境下的 SHCC-MEA 试验组的裂缝愈合效果不理想。 关键词：氧化镁膨胀剂；应变硬化水泥基复合材料；养护环境；自愈合；裂缝 中图分类号：TU528.57 文献标志码：A 文章编号：0454–5648(2019)11–1527–11 网络出版时间：2019–09–26 Effect of Curing Condition on Self-healing of Strain-Hardening Cement-Based Composite Crack Incorporating MgO Expansive Agent 1,2 1 1 1 1,2 ZHANG Peng , DAI Yuqing , GAO Kaikai , WANG Wentao , ZHAO Tiejun (1. College of Civil Engineering, Qingdao University of Technology, Qingdao 266033, Shandong, China; 2. Cooperative Innovation Center of Engineering Construction and Safety in Shandong Blue Economic Zone, Qingdao University of Technology, Qingdao 266033, Shandong, China) Abstract: A four-point test was utilized to induce cracks in the strain-hardening cement-based composite (SHCC) specimen (SHCC-MEA) with MgO expansive agent (MEA). The crack width and capillary water absorption at different curing time were measured. The effect of curing condition on the self-healing abilities of SHCC-MEA cracks was investigated. The microstructure of healing products was analyzed by scanning electron microscopy-energy dispersive spectrometry. The pre-cracked specimens were exposed to different curing conditions (i.e., dry (RH 50%), water fog (RH 95%), tap water and saturated Ca(OH)2 solution). The results