Development of Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) for bridge infrastructure applications

人们越来越需要耐用和有弹性的预制桥梁系统，以便快速完成现场活动，以最大限度地减少对出行公众的影响。预制桥梁可以提供更高质量、更快速和更安全的施工；然而，更多的异地预制桥梁组件需要更多地依赖这些组件之间现场安装的连接的长期性能。预制桥构件间材料的研究是近十年来兴起的。超高性能混凝土(UHPC)的力学性能和耐久性远远超过传统混凝土，这为显著提高这些现场应用的连接性能提供了机会，从而促进了预制桥面系统的更广泛使用。这里特别值得注意的是，超高性能混凝土在与先前浇筑的混凝土浇筑时可以表现出非凡的粘结力，并且可以 大大缩短了预制节点中嵌入离散钢筋的展开长度。最近，利用超高性能混凝土的特性重新设计预制桥梁组件之间的连接的概念在北美得到了认可。在加拿大和美国，预制式桥梁组件之间的现场浇注超高性能混凝土连接现在已经在很少的桥梁上实现。然而，需要研究开发超高性能混凝土以提高市场竞争力，这将反映出优化加拿大桥梁基础设施支出纳税人的资金。该项目是最近NSERC Engage赠款的延续，旨在进一步优化超高性能混凝土混合料的设计，并将其扩展到在混合料中包括钢纤维(UHPFRC)，用于 增强的强度和耐用性。

There is a growing need for durable and resilient prefabricated bridge systems which facilitate rapid completion of on-site activities in order to minimize the impact on the travelling public. Prefabricated bridges can provide higher quality, accelerated, and safer construction; however, greater offsite prefabrications of bridge components necessitates an increased reliance on the long-term performance of field-installed connections between these components. Research on the materials between precast bridge components has emerged in the last decade. Ultra-high performance concrete (UHPC) whose mechanical and durability properties far exceed those of conventional concretes present the opportunity to significantly enhance the performance of these field-applied connections, thus facilitating the wider use of prefabricated bridge deck systems. Of particular interest here, UHPCs can exhibit exceptional bond when cast against previously cast concrete and can significantly shorten the development length of embedded discrete bars into the precast joints. More recently, the concept of using the properties of UHPC to redesign the connections between prefabricated bridge components has been recognized in North America. Field-cast UHPC connections between prefabricated bridge components have now been implemented in few bridges in Canada and U.S. However, research is need to develop UHPC to increase market competitiveness that will reflect on optimizing spending tax payers' money in Canada's bridge infrastructure. This project is a continuation of a recent NSERC Engage grant to further optimize the design of UHPC mix and extend it to include steel fibers in the mix (UHPFRC) for enhanced strength and durability.