导　　师： 杜红秀

学科专业： H1406

授予学位： 硕士

作　　者： ;

机构地区： 太原理工大学

摘　　要： 近年来，随着大跨度桥梁、隧道以及高层建筑的蓬勃发展，强度高、耐久性好和工作性能优异的高强混凝土正得到日益广泛的应用。然而，高强混凝土与普通混凝土相比，结构密实，脆性更大，渗透性低，抗火性能差。而通过掺加聚丙烯纤维提高高强混凝土的韧性是当前的重要研究方向。同时对高强混凝土硬化早期的开裂有很好的改善作用。它能够很好的缓解混凝土硬化早期由于各种因素造成的拉伸应力，减少宏观裂缝的发生与发展，阻止基体中原有的微裂缝扩展并延缓新裂缝的出现，提高基体的变形能力。所以，研究掺入聚丙烯纤维后高强混凝土力学性能，寻求聚丙烯纤维的最佳掺量，具有重要理论意义和实用价值。
　　 本试验研究依托山西省高校科技开发研究项目(编号：2007115)“高强混凝土抗火增韧组分-聚丙烯纤维研究”，对聚丙烯纤维高强混凝土分别进行了立方体抗压试验、劈拉试验、弹性模量试验、轴心抗压试验、抗折试验；还按照国际结构与材料研究所联合会混凝土断裂力学技术委员会(RILEMTC50-FMC)已正式推荐的混凝土断裂能标准测试方法，用三点弯曲梁法研究了聚丙烯纤维高强混凝土的断裂能变化。在本试验中选择了六个不同的掺量和四种不同长度的聚丙烯纤维，研究掺量和纤维长度对聚丙烯纤维高强混凝土的影响，来确定纤维的最佳掺量和最佳长径比。同时还通过混掺两种、三种、四种不同长度的聚丙烯纤维，验证混杂纤维是否优于单一纤维长度的高强混凝土的各个力学性能。
　　 通过本试验研究，表明对于立方体抗压强度和轴心抗压强度方面，聚丙烯纤维对高强混凝土的影响较小，可以直接取高强混凝土的强度。但是对于拉压比、劈拉强度、弹性模量、抗折强度以及断裂能方面，聚丙烯纤维对高强混凝土的影响比较明显，表明了聚丙烯纤维的确改善了高强混凝土的韧性，并且随掺量和纤维长度有上升的趋势，同时混掺不同长度的聚丙烯纤维高强混凝土在抗折强度和断裂能力学性能方面还是优于单一长度的纤维高强混凝土。这些结论为聚丙烯纤维的研究提供了丰富的资料，还可以作为聚丙烯纤维高强混凝土结构设计和实际工程的应用的重要依据。 In recent years,as the broad bridge,the tunnel and the high building’s popularity,High-strength concrete with the characters of high intensity,good endurance and excellent utility is on application day by day. .However,comparing with the common concrete,the strict construction,the greater crisp character and the lower penetrability,lower firefighting properties. But adding the polypropylene fiber to improve the toughness of high strength concrete is an important direction in present study. Meanwhile, early cracking of high strength concrete hardening have a good improvement. It could well ease the early tensile stress of concrete hardening due to various factors, reduce the occurrence and development of macrco-crack ,prevent the expansion of the existing micro-cracks and delay the emergence of new cracks in the basal body and improve the ability of the matrix deformation.. Therefore the study about the mechanical properties of the high strength concrete with polypropylene fiber is a topic which has both the academic and realistic sense. Relying on shanxi university science and technology research and development program /(Numbers:2007115/)' polypropylene fiber of high strength concrete fire toughening components',this study of polypropylene fiber reinforced high strength concrete include cube compression tests、splitting tensile tests、elastic modulus tests、axial compression tests and bending tests refer to steel fiber concrete method. Finally, we studied the polypropylene fiber reinforced concrete fracture energy changes with three-point bending beam method in accordance with the RILEM guideline. We select six different dosages sizes and four different lengths of polypropylene fiber and determine the best content the best aspect ratio with the impact polypropylene fiber reinforced concrete. We also verify hybrid fiber mechanical properties of high strength concrete with different lengths compared to the single lengths . By the test results with the axial compressive strength and compressive strength, the impact of high-strength concrete with polypropylene fiber is very small and use high strength concrete strength directly. But for tension and compression ratio, splitting tensile strength, elastic modulus, flexural strength and fracture energy, changes in mechanical properties of polypropylene fiber reinforced high strength concrete is more obvious. It prove polypropylene fibers improve the toughness of high strength concrete and show upward changes with the content and fiber length. While hybrid fiber reinforced concrete in i flexural strength and fracture energy superior to the single length of fiber or high-strength concrete, but the advantage is not obvious. These conclusions for the study of polypropylene fibers provides a wealth of information and can also serve as the important basis of polypropylene fiber reinforced concrete structure design and practical application for the project.

关 键 词： 聚丙烯纤维 高强混凝土 力学性能 大跨度桥梁 隧道工程

分 类 号： [TU528.572 TU502.3]

领　　域： [建筑科学] [建筑科学]