Probabilistic life cycle analysis of alternative reinforcement products in the design of concrete structures - Phase One: Laboratory Durability Testing

在加拿大，桥梁暴露在恶劣的天气条件下。这种情况不仅导致混凝土的劣化，而且主要导致钢筋的锈蚀。老化的桥梁结构的恶化是一个令人担忧的问题。很大一部分问题是由于内部钢筋的腐蚀造成的。在加拿大的环境中，桥梁结构中内部钢筋的腐蚀速率是几个参数的函数，例如温度，即冻结和解冻周期，湿度和直接暴露在水塔中的水平，除冰盐的存在，持续和重复加载，以及时间。由于这些因素，混凝土失去了对内部钢筋的保护能力。未加保护的钢筋开始腐蚀的时间比预期的要早，因此缩短了桥梁的使用寿命。为了避免缩短使用寿命和安全的维护成本，开发了几种先进的防腐加固材料。在这项研究中，提出了几种类型的耐蚀钢筋的性能和耐久性试验，包括纤维增强聚合物(FRP)(玻璃FRP、碳纤维和玄武岩FRP)、马氏体微复合可成形钢(MMFX)和不锈钢，以及用于对比的常规未涂层钢。钢筋将被嵌入混凝土试件中，代表桥梁护墙。这些钢筋混凝土试件将暴露在恶劣的气候条件下，包括喷水和冻融循环，然后在暴露后测试极限容量。这项研究将从强度、耐久性、钢筋截面损失、延性和开裂模式等方面对材料性能进行评估，不仅为行业建立参考指南，而且主要是拓宽对所选材料在恶劣环境下行为模式的基础知识。预计不同类型的钢筋将影响混凝土梁在加载时的反应。作为研究的结果，将编写一份报告，总结所选材料的应用如何延长结构在恶劣天气下的使用寿命和降低维护成本。

In Canada, bridges are exposed to harsh weather conditions. Such conditions result not only in deterioration ofthe concrete but mainly lead to corrosion of the steel rebar. Deterioration of aging bridge structures represents agrowing issue. Significant part of the issue is due to corrosion of the internal reinforcement. In Canadianenvironment, the rate of corrosion of the internal reinforcement in bridge structures is a function of severalparameters such as temperature, i.e., cycles of freezing and thawing, level of humidity and direct exposure towater, presence of de-icing salts, sustained and repetitive loads, and time. Due these factors, concrete loses itsability to protect the internal reinforcement. Unprotected reinforcement starts to corrode sooner thananticipated and, therefore, reduces the bridge service life. To avoid shortening of the service life, and safe costof maintenance, several types of advanced corrosion resistant reinforcing materials have been developed.In this research, performance and durability testing is proposed on several types of corrosion resistantreinforcing rebars including Fibre Reinforced Polymer (FRP) (Glass FRP, Carbon FRP and Basalt FRP),Martensitic Micro-composite Formable Steel (MMFX), and Stainless steel, in addition to the conventionaluncoated steel for comparison purposes. The reinforcing bars will be embedded in concrete specimensrepresenting a bridge parapet. These reinforced concrete specimens will be exposed to severe weatherconditions including spraying water and cycles of freezing and thawing then tested for ultimate capacity afterthe exposure. The study will evaluate material performance in terms of strength, durability, section loss of therebar, ductility, and cracking patterns to not only establish reference guidelines for the industry but mainlybroaden the fundamental knowledge about the behavioral patterns of selected materials in harsh environments.It is expected that the different types of rebars will influence the response of the concrete beams when loaded.As an outcome of the study, a report will be prepared summarizing how the application of the selectedmaterials can extend the service life and reduce the maintenance cost of structures exposed to harsh weather.