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

纤维增强聚合物（FRP）钢筋由于其优异的耐久性性能，在建筑行业中已成为传统钢筋的有前途的替代品。FRP筋具有非腐蚀性，有效地解决了混凝土结构中钢腐蚀引起的退化的主要问题。钢铁腐蚀可能导致民用基础设施的维修费用过高和脆性灾难性故障（例如莫兰迪桥的倒塌）。尽管FRP棒具有无腐蚀的特性，但当暴露在潮湿条件下（例如，在混凝土裂缝位置），其基体/树脂成分会塑化，并因化学侵蚀而降解。这对于用FRP筋加固的混凝土结构的基体主导性能更为关键，例如FRP筋的粘结强度、剪切强度和横向抗压强度。本项目重点对玻璃纤维增强聚合物（GFRP）和玄武岩纤维增强聚合物（BFRP）棒材在各种环境条件下的长期性能进行全面检查，模拟恶劣环境条件，包括高温、盐水和碱性暴露，以评估GFRP和BFRP棒材的性能。该项目旨在创建一个测试协议，将FRP在加速老化条件下的耐久性性能和短期暴露与实际现场条件联系起来。我们感兴趣的关键变量是frp中树脂主导的性能和应力条件的影响。本试验方案将阐明在实验室条件下采用的常用加速老化试验的可靠性。对树脂样品和FRP条都采用了测试方案，以深入了解单个成分、纤维、基体的性能，以及FRP系统对纤维-基体界面的计算。FRP筋在应用应力下的潜在结合增加了一个关键的维度，通过检查其在暴露于恶劣环境下的承载条件下的降解特性，密切模仿现实世界的应用。FRP筋将在暴露于正常和加速条件下进行检测，以测量其层间和横向剪切强度。将未暴露FRP筋和预暴露FRP筋浇筑在混凝土梁和砌块中，以测量暴露降解对混凝土结构中FRP筋粘结和抗弯性能的影响。将树脂样品分别浇铸、暴露和测试，以观察直接暴露于纯树脂样品后的拉力和剪切测试效果。用于了解所使用方案加速效应的暴露类型将是通过比较直接暴露在碱性混合物中的FRP样品的降解效果，该混合物复制了混凝土的pH值和化学性质，但在高温下增加了向复合材料的扩散。该项目的成果为建筑行业和可持续发展的努力提供了广泛的好处：提高基础设施的耐久性：FRP筋的发展改善了长期性能，可以延长混凝土结构的使用寿命，从而降低维护成本，增强可持续性。推进净零建筑：使用FRP筋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：新建立的加速协议可以很容易地被整个建筑行业采用，以评估FRP筋的耐久性，确保建筑项目的可靠性和安全性。该项目深入研究了纤维增强聚合物（FRP）钢筋作为传统钢筋的耐用替代品的前景，同时致力于更可持续和耐用的方法。

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.