Characterization of Environment-Assisted Subcritical Debond of Bonded Repairs/Strengthening of Aging Infrastructure

这项研究的主要目标是开发一种变革性的方法来了解退化机理和评估FRP-混凝土界面的长期耐久性。该方法包括a)定量表征环境辅助下FRP-混凝土界面亚临界脱粘生长的动力学，b)建立侵蚀性环境中FRP-混凝土界面基于机理的退化模型。建议的亚临界脱粘试验可以模拟FRP-混凝土界面在使用寿命期间发生的破坏，允许在试验过程中与环境物种相互作用，并减少由于混凝土养护、长期混凝土强度增长、环氧徐变和环氧养护等竞争效应而与断裂能相关的模糊性。该项目将为FRP加固结构的长期耐久性研究和应用提供一条新的途径，从而对FRP材料在混凝土基础设施中的研究和应用产生立竿见影的影响。PIS提出了一项积极的教育计划，旨在补充研究活动，重点是招募传统上代表性较低的不同群体(女性、农村、少数群体和/或社会经济条件较差的学生)参加拟议的活动。根据拟议的研究工作，将开发一系列教学模块，并将其融入PI部门的课程。将通过工程学院计划，为阿拉巴马州经济停滞地区的少数民族高中生举办一次基于这项研究的研讨会。代表不足的高中生和本科生将有机会参与这一项目。基于这项研究的研讨会将提供给来自历史上黑人学院和大学的科学和工程教师。

The major objective of this research effort is to develop a transformative approach to understand the degradation mechanism and assess the long-term durability of the FRP-to-concrete interface. This approach consists of a) quantitatively characterizing the kinetics of environment-assisted subcritical debond growth along the FRP-to-concrete interface, and b) development of a mechanism-based degradation model for the FRP-to-concrete interface in aggressive environments. The proposed subcritical debond testing closely simulates the failure occurring during the service-life of the FRP-to-concrete interface, allows interaction with environmental species during testing, and reduces ambiguity associated with fracture energy due to competitive effects of concrete curing, long-term concrete strength gaining, epoxy creep, and epoxy curing.This project will have immediate effects on research and applications of FRP materials in concrete infrastructure by providing a new avenue to study and account for the long-term durability of FRP strengthened structures. The PIs propose an aggressive educational plan designed to be complementary to the research activities with focus on recruiting a diverse group of traditionally underrepresented (female, rural, minority and/or socio-economically disadvantaged) students to participate in the proposed activities. A series of teaching modules will be developed based on the proposed research endeavor and blended into the curriculum of the PI's department. A workshop based on this study will be held for minority high school students from economically stagnant areas in Alabama through the Engineering Academy program. Underrepresented high school students and undergraduate students will have opportunities to participate in this project. Seminars based on this study will be given to science and engineering faculty from historically black colleges and universities.