UHPC的轴拉性能与裂缝宽度控制能力研究

发布时间：2018-01-28 13:50

本文关键词： 超高性能混凝土轴拉应力-应变曲线应变强化应变软化裂缝宽度控制　出处：《哈尔滨工业大学学报》2017年12期 　论文类型：期刊论文

【摘要】：为研究3种类型超高性能混凝土(ultra-high performance concrete,简称UHPC)的轴拉应力-应变曲线及其裂缝宽度控制能力,包括高应变强化UHPC、低应变强化UHPC和应变软化UHPC.采用轴拉试验方法测试狗骨头形试件,得到UHPC的轴拉应力-应变曲线和缝宽-应变曲线.试验结果表明:高应变强化UHPC和低应变强化UHPC的轴拉应力-应变曲线均包括弹性段、应变强化段和应变软化段,应变软化UHPC只有弹性段和应变软化段;UHPC应变强化段和应变软化段的转折点是裂缝缓慢扩展和迅速扩展的临界点;提高UHPC的极限拉伸应变,即延长其应变强化段,有助于提高其裂缝宽度控制能力;高应变强化UHPC拉伸应变在0.42%之前,其裂缝宽度均小于0.05 mm.对比C50混凝土(极限应变、极限强度分别为0.012%、2.3 MPa),高应变强化UHPC优异的裂缝宽度控制能力避免了结构设计中受正常使用状态裂缝宽度验算限制的影响,同时可在钢筋屈服前与其全程协同工作,这使得钢筋增强高应变强化UHPC在某些需要对裂缝宽度进行严格控制的结构类型中具有很高的应用价值.
[Abstract]:In order to study three types of ultra-high performance concrete of ultra-high performance concrete (UHPC). The axial tensile stress-strain curve and its crack width control ability, including high strain strengthening UHPC. Low strain strengthened UHPC and strain softening UHPC were used to test the dog bone specimens. The axial tensile stress-strain curves and slit width-strain curves of UHPC are obtained. The experimental results show that the axial tensile stress-strain curves of UHPC with high strain strengthening and UHPC with low strain strength include elastic segments. Strain hardening and strain softening phase, strain softening UHPC only elastic and strain softening phase; The turning point of UHPC strain strengthening section and strain softening stage is the critical point of slow and rapid crack propagation. Increasing the ultimate tensile strain of UHPC, that is, prolonging its strain strengthening section, will help to improve its crack width control ability. The crack width of high strain strengthened UHPC is less than 0. 05 mm before 0.42%. Compared with C50 concrete, the ultimate strain and ultimate strength are 0.012% respectively. The excellent crack width control ability of high strain strengthened UHPC avoids the influence of checking calculation of crack width in normal service state in structural design. At the same time, it can work with the steel bar in the whole process before yielding, which makes the reinforced reinforced high strain strengthened UHPC have high application value in some structural types which need to strictly control the crack width.
【作者单位】：先进土木工程材料教育部重点实验室(同济大学);同济大学土木工程学院;上海罗洋新材料科技有限公司;
【基金】：国家自然科学基金青年基金(51609172) 上海市浦江人才计划(16PJ1409900) 上海市科委项目(17DZ1204200)
【分类号】：TU528
【正文快照】： 超高性能混凝土(ultra-high performanceconcrete,简称UHPC)是一种具备高强度、高韧性、低孔隙率、高耐久性的纤维增强水泥基材料,被公认为未来极具发展前景和应用价值的一种新型结构材料[1].UHPC 20世纪70年代起源于丹麦,八九十年代在欧洲进行了比较系统深入的研究,并开始在

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