Rapid migration chloride test for Ultra High Performance Fiber Reinforced Concrete

北美民用基础设施系统，如道路、桥梁、立交桥、海事和机场设施， 由于恶劣的气候条件和化学侵蚀，混凝土面临过早老化的问题。在这 超高性能纤维增强混凝土（UHPFRC）是一种新型的水泥基材料， 因其在基础设施应用中出色的延展性和耐久性而崭露头角。 UHPFRC是一种新型的水泥基复合材料，具有高度致密的水泥基基体， 最佳的纤维系统。UHPFRC具有优异的力学性能， 延展性和韧性。因此，UHPFRC对耐久性问题具有很高的抵抗力，例如， 和解冻和盐结垢，如实验室测试所证明的。 UHPFRC的使用可以有效地节省材料，而且可以保证结构的世纪寿命 在最恶劣的海洋环境下。然而，目前的加速测试 表征混凝土中氯离子的渗透速率不适用于UHPFRC，因为基质致密。 目前迫切需要提供有意义的氯离子扩散系数来预测寿命 UHPFRC结构。 研究的目的有四个：（1）开发一种适用于 研究了两种纤维对氯离子迁移的影响 研究了氯离子对UHPFRC徐变性能的影响; 将计算结果与真实的海洋环境条件进行比较，以获得一个总体的认识。提供 科学的方法来评估UHPFRC的寿命将有助于决策者投资于更耐用的 我们的基础设施解决方案。

North American civil infrastructure systems, such as, roads, bridges, overpasses, marine and airport facilities, are facing premature concrete deterioration due to the severe climatic conditions and chemical attacks. In this context, new cement based materials Ultra High Performance Fiber Reinforced Concrete (UHPFRC) have been emerging for their outstanding ductility and durability properties in infrastructure applications. UHPFRC is a new class of cement-based composites with a highly compact cementitious matrix reinforced by an optimal system of fibers. UHPFRC are endowed with outstanding mechanical properties in terms of ductility and toughness. As a consequence, UHPFRC are highly resistant to durability issues, such as, freeze and thaw and salt scaling as proven by laboratory tests. The use of UHPFRC can effectively imply material saving, but also guarantee a structure lifetime of a century under the most severe environmental marine environment. However, the current accelerated tests for characterizing the penetration rate of chloride in concrete do not apply for UHPFRC due to the dense matrix. There is today a critical need to provide meaningful chloride diffusion coefficients for predicting the life time of UHPFRC structures. The research objective is fourfold: (1) To develop an accelerated migration test which is suitable for characterizing the chloride migration for UHPFRC; (2) To study the effect on chloride transport for two fiber kinds and level of microcracking; (3) To study the effect of chloride on the creep properties of UHPFRC; (4) to compare the results with real marine environmental conditions for a general comprehension. Providing a scientific approach to evaluate the lifetime of UHPFRC will help decision makers to invest in more durable solutions for our infrastructures.