A New Performance-Based Test for Assessing Chloride-Induced Reinforcement Corrosion Resistance of Geopolymer Mortars

• Published in: Materials 2024-10, Vol.17 (21), p.5162
• Main Authors: Ichimiya, Kazuo, Yamamoto, Rieru, Ikeda, Ko, Nguyen, Quang Dieu, Castel, Arnaud
• Format: Article
• Language: English
• Subjects: Cement; Charge transfer; Chloride; Chloride ions; Chloride resistance; Concrete mixing; Concrete structures; Corrosion; Corrosion potential; Corrosion rate; Corrosion resistance; Corrosion tests; Curing; Durability; Electric potential; Geopolymers; Humidity; Performance tests; Permeability; Permeability tests; Propagation; Reinforcement; Steel; Test procedures; Testing time
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17215162

The widespread adoption of geopolymer concretes in the industry has been slow, mainly due to concerns over their long-term performance and durability. One of the main causes of concrete structures' deterioration is chloride-induced corrosion of the reinforcement. The reinforcement corrosion process in concrete is composed of two main stages: the initiation phase, which is the amount of time required for chloride ions to reach the reinforcement, and the propagation phase, which is the active phase of corrosion. The inherent complexities associated with the properties of precursors and type of activators, and with the multi-physics processes, in which different transfer mechanisms (moisture, chloride, oxygen, and charge transfer) are involved and interact with each other, have been a major obstacle to predicting the durability of reinforced alkali-activated concretes in chloride environments. Alternatively, the durability of alkali-activated concretes can be assessed through testing. However, the performance-based tests that are currently available, such as the rapid chloride permeability test, the migration test or the bulk diffusion test, are only focusing on the initiation phase of the corrosion process. As a result, existing testing protocols do not capture every aspect of the material performance, which could potentially lead to misleading conclusions, particularly when involving an electrical potential to reduce the testing time. In this paper, a new performance-based test is proposed for assessing the performance of alkali-activated concretes in chloride environments, accounting for both the initiation and propagation phases of the corrosion process. The test is designed to be simple and to be completed within a reasonable time without involving any electrical potential.