摘要
对已有应变硬化水泥基复合材料薄板型试件的直接拉伸试验方法进行改进,并利用改进后的测试方法研究超高韧性水泥基复合材料(Ultra High Toughness Cementitious Composite,简称UHTCC)的受拉性能,通过试验系统地给出利用国产基体原材料配制的超高韧性水泥基复合材料的直接拉伸特性,具体包括直接拉伸应力-应变曲线和极限裂缝宽度等特征指标。试验结果表明,所研制的超高韧性水泥基复合材料的极限拉应变可以稳定地达到3%以上,并具有良好的裂缝宽度控制能力,在荷载达到峰值的情况下对应的裂缝宽度可以有效地控制在100μm以内,有些甚至在50μm以内,可称为"无缝混凝土"。还利用该方法对具有不同初始缝高比的双边对称开口薄板试件进行系统地研究,试验表明超高韧性水泥基复合材料对缺口不敏感,即使在初始缝高比达到0.5的情况下,超高韧性水泥基复合材料仍具有显著的应变硬化性能及良好的裂缝无害化分散能力。超高韧性水泥基复合材料这些优异的性能将使其在结构防裂、防水、抗震、耐久性修补与防护等方面发挥显著作用。
A modified uniaxial tensile test method is presented for ultra-high toughness cementitious composites （UHTCC）. The method is employed to test the uniaxial tensile properties of UHTCCs made of domestic raw materials except PVA fiber. Tests of un-notched plate specimens show the UHTCCs possess significant pseudo strain hardening properties and excellent crack width control capability, with the corresponding ultimate tensile strains steadily reaching above 3% and the average ultimate tensile crack width being well below 100μm. Tests of double edge symmetrically notched specimens show that the UHTCCs are insensitive to notches, with significant pseudo strain hardening behavior and harmful cracks being dispersed into multiple harmless ones even when the initial notch/depth ratio reaches 0. 5. These excellent properties of UHTCC will make it play more important roles in future applications for controlling crack width,preventing leaching, resisting earthauake and durable structural retrofitting.
出处
《土木工程学报》
EI
CSCD
北大核心
2009年第9期32-41,共10页
China Civil Engineering Journal
基金
国家自然科学基金重点项目(50438010)
南水北调工程建设重大关键技术研究及应用(JGZXJJ2006-13)
