Durability of Fibre Reinforced Polymer (FRP) rods in low carbon concrete

纤维增强聚合物(FRP)筋由于其优异的耐久性性能，在建筑业中已成为一种有前途的传统钢筋的替代方案。FRP筋具有非腐蚀性，有效地解决了混凝土结构中钢筋腐蚀引起的退化这一主要问题。钢材腐蚀可能导致民用基础设施维修成本过高，并导致脆弱的灾难性故障(如莫兰迪大桥坍塌)。尽管玻璃钢棒具有防腐蚀的特性，但当暴露在潮湿条件下(例如，在混凝土裂缝位置)时，其基质/树脂组分会塑化，并因化学侵蚀而降解。这对FRP筋混凝土结构的粘结强度、剪切强度和横向抗压强度等以基质为主的性能更为关键。本项目旨在通过模拟高温、盐碱暴露等侵蚀性环境条件，对玻璃纤维增强聚合物(GFRP)和玄武岩纤维增强聚合物(BFRP)筋在不同环境条件下的长期性能进行全面检测，以评估GFRP和BFRP筋的性能。该项目旨在建立一种将FRP在加速老化和短期暴露条件下的耐久性能与现场实际条件相关联的测试方案。感兴趣的关键变量是树脂在FRPS中的主导性能和应力条件的影响。该试验方案将阐明实验室条件下常用的加速老化试验的可靠性。测试方案适用于树脂样品和FRP棒，以深入了解单个组分、纤维、基质的性能，同时FRP系统也对纤维-基质界面进行核算。FRP筋在外加应力作用下的潜在结合增加了一个重要的维度，通过检测其在承受载荷条件下暴露在侵蚀性环境中时的退化特性，紧密模拟真实世界的应用。FRP筋将在暴露于正常和加速条件下进行检查，以进行测试，以测量其层间和横向剪切强度。将未暴露和预暴露的FRP筋浇注在混凝土梁和砌块中，以测量暴露退化对混凝土结构中FRP筋的粘结和抗弯性能的影响。树脂样品将分别浇注、曝光和测试，以观察在进行拉伸和剪切测试后直接暴露于纯树脂样品的效果。用于了解所用方案加速效果的暴露类型将通过比较直接暴露在碱性混合物中的FRP试件的降解效果，该混合物复制了混凝土的pH和化学成分，但在高温下增加了对复合材料的扩散。该项目的结果为建筑业和可持续发展努力提供了广泛的好处：a.增强基础设施耐久性：开发具有更好的长期性能的FRP筋可以延长混凝土结构的使用寿命，从而降低维护成本并增强可持续性。推进净零排放建设：利用玻璃钢加固的低碳混凝土与英国的净零排放目标无缝对接，使这项研究与可持续发展目标直接相关。全行业采用：新制定的加速规程可以很容易地在整个建筑业中采用，以评估FRP筋的耐久性，确保建筑项目的可靠性和安全性。该项目深入探讨了纤维增强聚合物(FRP)筋作为建筑中传统钢筋的耐久替代品的前景，同时努力寻求更可持续和更耐用的方法。

Fiber-Reinforced Polymer (FRP) bars have emerged as a promising alternative to conventional steel reinforcement in the construction industry due to their superior durability performance. FRP bars exhibit non-corrosive properties, effectively addressing the primary issue of steel corrosion-induced degradation in concrete structures. Steel corrosion can lead to prohibitive repair costs in civil infrastructure and brittle catastrophic failures (e.g., the collapse of Morandi bridge). Despite the corrosion-free nature of FRP rods, their matrix/resin component plasticises when exposed to humid conditions (e.g., at a concrete crack location) and degrades due to chemical attack. This is more critical for matrix dominated properties of concrete structures reinforced with FRP bars such as the bond, shear and transverse compressive strength of FRPs. This project focuses on a comprehensive examination of the long-term performance of Glass Fiber Reinforced Polymer (GFRP) and Basalt Fiber Reinforced Polymer (BFRP) bars under various environmental conditions by simulating aggressive environmental conditions, including elevated temperatures, saline, and alkaline exposures, to evaluate the performance of GFRP and BFRP bars.The project aims to create a test protocol that correlates FRP durability performance under accelerated ageing conditions and short-term exposures with actual on-site conditions. Key variables of interest are resin dominated properties in of FRPs and effect of stress conditions. This test protocol will shed light on the reliability of commonly applied accelerated ageing tests adopted in lab conditions. The test protocol is adopted for both resin samples and FRP bars to obtain an in-depth understanding of how the individual constituents, fiber, matrix perform but also the FRP system performs accounting also for fiber-matrix interfaces. The potential incorporation of FRP bars under applied stresses adds a crucial dimension by examining their degradation properties when subjected to load-bearing conditions while exposed to aggressive environments, closely mimicking real-world applications.FRP bars will be examined after being exposed to normal and accelerated conditions to be tested to measure their interlaminar and transverse shear strength. Non-exposed and pre-exposed FRP bars will be cast in concrete beams and blocks to measure the effect of exposure degradation on the bond and flexural performance of FRP bars in concrete structures. Resin samples will be cast, exposed, and tested separately to see the effect of direct exposure to pure resin samples after being tested in tension and shear. The type of exposure that will be used to understand the acceleration effect of the used protocol will be by comparing the degradation effect of directly exposed FRP samples in an alkaline mixture that replicates the pH and chemistry of concrete but at elevated temperatures to increase the diffusion to the composite material.The outcomes of this project offer wide-ranging benefits to the construction industry and sustainability endeavors:a. Enhanced Infrastructure Durability: The development of FRP bars with improved long-term performance can extend the lifespan of concrete structures, resulting in reduced maintenance costs and enhanced sustainability.b. Advancing Net-Zero Construction: The utilization of low carbon concrete reinforced with FRP bars aligns seamlessly with the UK's net-zero emissions targets, making this research directly relevant to sustainability goals.c. Industry-Wide Adoption: The newly established acceleration protocol can be readily adopted across the construction industry to assess the durability of FRP bars, ensuring the reliability and safety of construction projects.This project delves into the promising realm of Fiber-Reinforced Polymer (FRP) bars as a durable alternative to traditional steel reinforcement in construction while working towards more sustainable and durable approaches.