云蒙山特大桥聚丙烯纤维混凝土力学性能指标及其相关性研究  

Mechanical Properties and Correlation of PPF Concrete of Yunmengshan Bridge

作　　者：吴伟军 WU Weijun(Shanghai Highway Bridge(Group)Co.,Ltd.,Shanghai200433,China)

机构地区：[1]上海公路桥梁(集团)有限公司,上海200433

出　　处：《施工技术（中英文）》2024年第6期161-165,共5页Construction Technology

基　　金：河南省重点研发与推广专项(202102310255);上海公路桥梁(集团)有限公司科研项目(2020-KY-3)。

摘　　要：以S317线云蒙山特大桥箱梁C55聚丙烯纤维混凝土为研究对象,开展材料力学性能与机理研究,对聚丙烯纤维混凝土施加预应力的龄期提出技术建议,根据试验结果建立力学指标的定量关系。主要研究结论如下:混凝土3d, 7d抗压强度分别达到设计强度的103.5%,114.2%,3d, 7d劈裂抗拉强度分别达到轴心抗拉设计强度的104.0%,120.4%,均满足施加预应力要求,28d抗压强度与劈裂抗拉强度性能十分优异,微观试验结果与力学性能测试结果一致。混凝土5d动弹性模量为28d的87.7%,5d静弹性模量为28d的83.2%,考虑到聚丙烯纤维混凝土的抗裂性能优异,对混凝土施加预应力可考虑在龄期5d时进行。聚丙烯纤维混凝土力学性能指标间具有良好相关性。在实际工程中,基于力学性能指标的相关关系,可通过更易获取混凝土的抗压强度实测值或动弹性模量实测值间接掌握混凝土的抗拉性能和刚度的发展规律,从而为工程施工提供技术依据。Taking C55polypropylene fiber concrete of the box girder of Yunmengshan Bridge on S317 line as the research object,the mechanical properties and mechanism of materials are systematically studied,the technical suggestions on the age of prestress of polypropylene fiber concrete are put forward,and the quantitative relationship of mechanical indexes is established according to the test results.The main research conclusions are as follows:The 3d and 7d compressive strength of concrete reaches 1035%and 1142%of the design strength respectively,and the 3d and 7d splitting tensile strength reaches 1040%and 1204%of the axial tensile design strength respectively,which meet the requirements of prestress.The 28d compressive strength and splitting tensile strength are very excellent,and the micro test results are consistent with the mechanical property test.The 5d dynamic elastic modulus of concrete is 877%of the 28d dynamic elastic modulus,and the 5d static elastic modulus is 832%of the 28d static elastic modulus.Considering the excellent crack resistance of polypropylene fiber concrete,the prestress of concrete can be carried out at the age of 5d.There is a good correlation between the mechanical properties of polypropylene fiber reinforced concrete.In practical engineering,based on the correlation of mechanical performance indexes,the development law of tensile performance and stiffness of concrete can be indirectly mastered by making it easier to obtain the measured value of compressive strength or dynamic elastic modulus of concrete,so as to provide technical basis for engineering construction.

关 键 词：桥梁工程 聚丙烯纤维混凝土 力学性能 弹性模量 

分 类 号：U444[建筑科学—桥梁与隧道工程]