The use of UHPC in accelerated bridge construction

UHPC 在加速桥梁施工中的应用

• 批准号: RGPIN-2021-03760
• 负责人: Svecova, Dagmar
• 金额: $ 1.89万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=749431
• 关键词: use; UHPC; accelerated; bridge; construction

Ultra-high performance concrete (UHPC) is a new construction material exhibiting rapid strength gains, strengths four times higher than concrete, and excellent durability. Over the last decade, the use of UHPC in bridge construction has increased. Between 2006 and 2019, over 300 bridges with UHPC components were built in the United States and Canada. Most frequent use of UHPC is in field-cast construction joints, or as bridge overlays. Rapid bridge deck construction minimizes the time that critical transportation infrastructure is out of service, and UHPC is capable of enabling this. High quality deck panels can be prefabricated, but field-casting high quality joints remains a challenge. Poor quality joints are detrimental to overall bridge deck durability. Bond strength plays a significant role in the shear transfer between precast bridge girders and field-cast connections. The proposed research focuses on determining the bond strength of UHPC with precast concrete, and cast-in-place UHPC. The goal of this research program is to quantify important bond parameters and to modify existing design equations governing shear transfer in bridge deck UHPC joints. Several studies on bond performance between UHPC and precast concrete under static load, including two completed by the applicant's research group, found increase in interface bond strength with the degree of substrate roughness. The results however are qualitative rather than quantitative at this time. This research program will use several methods to assess surface roughness in order to establish quality control and construction protocols for measurement of roughness when UHPC is used in field-cast joints. Coefficient of friction and cohesion/adhesion will be determined, as function of surface roughness and UHPC age. This will lead to optimization of the design of UHPC connections. This research program will investigate the shear friction mechanism for both UHPC-concrete, and UHPC- cast in place UHPC interface. Design equations will be developed for shear friction mechanism as function of reinforcement ratio, roughness and UHPC age under static and cyclic loads. This research program will investigate fatigue behavior of UHPC interface bond, a topic that has yet to be effectively studied. The results of this research program will provide engineers with design values of critical bond parameters, such as cohesion and friction, and guidelines for optimization of joint reinforcement. It will also develop methods for evaluating critical parameters on the construction site leading to more controlled outcomes and better long-term joint performance. This research program will train seven HQP in understanding this leading edge construction material behaviour, application, and design. Because design standards for use of UHPC are currently under development, I will bring my HQP as observers to the discussions that are held in the ACI and CSA committees.

超高性能混凝土（UHPC）是一种强度增长快、强度比混凝土高4倍、耐久性好的新型建筑材料。在过去的十年中，UHPC在桥梁建设中的使用有所增加。在2006年至2019年期间，美国和加拿大建造了300多座采用UHPC组件的桥梁。UHPC最常见的用途是现场浇筑施工缝，或作为桥梁覆盖层。快速桥面施工可最大限度地缩短关键交通基础设施的停运时间，UHPC能够实现这一点。高质量的桥面板可以预制，但现场铸造高质量的接头仍然是一个挑战。质量差的接缝对桥面板的整体耐久性不利。粘结强度在预制桥梁梁和现浇节点之间的剪力传递中起着重要作用。 建议的研究重点是确定UHPC与预制混凝土和现浇UHPC的粘结强度。本研究计划的目标是量化重要的粘结参数，并修改现有的设计公式控制剪切传递桥面UHPC节点。 在静态荷载下，对UHPC和预制混凝土之间粘结性能的几项研究（包括申请人的研究小组完成的两项研究）发现，界面粘结强度随着基底粗糙度的增加而增加。然而，目前的结果是定性的，而不是定量的。本研究计划将使用几种方法来评估表面粗糙度，以便在现场浇筑接缝中使用UHPC时建立粗糙度测量的质量控制和施工方案。将确定摩擦系数和内聚力/粘附力，作为表面粗糙度和UHPC龄期的函数。这将导致UHPC连接设计的优化。本研究计画将探讨超高混凝土与混凝土、超高混凝土与现浇超高混凝土界面之剪摩擦机制。设计公式将开发剪切摩擦机制作为函数的钢筋比率，粗糙度和UHPC年龄在静态和循环荷载。本研究计划将探讨UHPC界面粘结的疲劳行为，这是一个尚未得到有效研究的课题。 本研究计划的结果将为工程师提供关键粘结参数的设计值，如凝聚力和摩擦力，并为接头加固的优化提供指导。它还将开发用于评估施工现场关键参数的方法，从而实现更可控的结果和更好的长期联合性能。这项研究计划将培训七名HQP了解这种前沿建筑材料的行为，应用和设计。由于UHPC的设计标准正在制定中，我将带我的HQP作为观察员参加ACI和CSA委员会的讨论。