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）是一种新型建筑材料，具有快速强度增长、强度比混凝土高四倍以及优异的耐久性。在过去的十年中，UHPC 在桥梁建设中的使用有所增加。 2006 年至 2019 年间，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停止服务的时间，而 UHPC 能够实现这一点。高质量的甲板面板可以预制，但现场铸造高质量接头仍然是一个挑战。接头质量差不利于桥面的整体耐用性。粘结强度在预制桥梁大梁和现场浇筑连接之间的剪切传递中起着重要作用。 拟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。该研究项目的目标是量化重要的粘结参数并修改控制桥面 UHPC 接头剪切传递的现有设计方程。 关于静态荷载下 UHPC 和预制混凝土之间的粘结性能的几项研究，包括由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材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。该研究计划将使用多种方法来评估表面粗糙度，以便建立在现场浇注接头中使用 UHPC 时测量粗糙度的质量控制和施工协议。将确定摩擦系数和内聚力/粘附力，作为表面粗糙度和 UHPC 寿命的函数。这将导致 UHPC 连接设计的优化。该研究计划将研究 UHPC-混凝土和 UHPC-现浇 UHPC 界面的剪切摩擦机制。将开发剪切摩擦机制的设计方程，作为静载荷和循环载荷下配筋率、粗糙度和 UHPC 寿命的函数。该研究计划将研究 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。 该研究项目的结果将为工程师提供关键粘结参数的设计值，例如内聚力和摩擦力，以及接头加固优化的指南。它还将开发评估施工现场关键参数的方法，从而实现更受控的结果和更好的长期接头性能。该研究计划将培训七名总部人员，让他们了解这种前沿建筑材料的行为、应用和设计。由于使用 UHPC 的设计标准目前正在制定中，因此我将带领我的 HQP 作为观察员参加 ACI 和 CSA 委员会举行的讨论。