Reinforced Concrete (RC) structures are vital to the US’s civil infrastructure for their strength and versatility. Unfortunately, RC elements deteriorate rapidly when exposed to corrosive environments. One possible solution is to extend the life of RC elements and systems using microencapsulated corrosion inhibitors to reduce the rebar corrosion rate. The capsules house an anodic corrosion inhibitor agent including calcium nitrate (CN) and triethanolamine (TEA). The integration of such microencapsulated materials will enhance the durability and extend the useful life by controlling the corrosion precursors and the corrosion process during damage evolution. Therefore, this work aims to develop and characterize the performance of microcapsules containing corrosion inhibitors (CN-C and TEA-C) in comparison to those introduced as admixtures (CN-A and TEA-A) for reinforced concrete applications. For the corrosion tests, all samples were subjected to continuous ponding, wet/dry cycles, and fog chamber exposure to simulate different environments. The results showed that TEA-C is more effective in giving a corrosion protection than TEA-A and the Control. In contrast, the corrosion protection performance of both CN-A and CN-C was alike. The corrosion kinetics was slightly reduced on inhibited rebars compared to unprotected rebars (the Control). When comparing TEA-C and CN-C, in the presence of each stimulus (pH changes for TEA-C, cracks for CN-C), TEA-C protected the rebar better than CN-C. For the admixture samples (TEA-A and CN-A) that do not need stimuli in the concrete, a stable and better corrosion protection was provided by CN-A. The outcome of this proof-of-concept study in the laboratory validates the merit of the proposed technology for corrosion control in RC structures.
Castaneda, Homero; Hassan, Marwa; Radovic, Miladin; and Milla, Jose, "Self-Healing Microcapsules as Concrete Aggregates for Corrosion Inhibition in Reinforced Concrete" (2018). Publications. 17.