Characterizing Corrosion Control and Prevention Methods for RC Elements Based on Hybrid Protection Mechanism

Project Details









Momen Mousa, Homero Castanada, Brendy Rincon


Office of the Assistant Secretary of Research and Technology


Coatings, Corrosion protection, Inhibitors (Chemistry), Materials, Reinforced concrete

Project description

A team comprised of Texas A&M University (TAMU) and University of Texas at San Antonio (UTSA) proposes a study that will include integration from the civil engineering, materials sciences and corrosion science technical communities to characterize and select the corrosion and mitigation methods for reinforced concrete (RC) elements regarding the corrosion of steel used in transportation applications. The proposal includes: (1) different corrosion control mechanisms including the mass transport resulted from the physical barrier (organic coatings), sacrificial or charge transfer mechanisms (cathodic protection, galvanic coupling) and homogeneous processes influencing redox inhibition (corrosion inhibitor) for corrosion of rebar steel embedded in concrete structures; (2) the characterization of RC elements with either or a combination of three different corrosion control methods, and evaluation of their performance to understand their influence on corrosion and its rates; and (3) identification of the most suitable and efficacy corrosion control strategy and quantify the uncertainties associated with methods for testing and monitoring corrosion of steel in RC elements in laboratory and field conditions. RC structures are frequently exposed to aggressive/corrosive environments that can promote deterioration of their structural properties and shortening of their service life. Chloride-induced corrosion of reinforcing steel in concrete represents one of the most severe and common forms of RC degradation. The high alkaline pH of concrete leads to the formation of a passive film on the reinforcing steel. Diffusion and accumulation of chloride ions within the concrete matrix promotes breakdown of the ferrous passive film and initiation of localized corrosion at the steel surface. This passive film breakdown process requires a critical chloride concentration, commonly known as “threshold” chloride concentration. In the case where a sacrificial inorganic layer such as Zinc is applied on the rebar, corrosion initiation could be defined as the failure of the Zn layer at a certain location. The localized attack can be influenced, as mentioned previously, by the chloride content, but also by other parameters such as temperature, corrosion products thickness, etc. Previous works and efforts have been mostly focused in the threshold chloride concentration at the steel/concrete interface. The literature on galvanized steel is limited; however, it is known that the threshold chloride concentration for this material is greater than for bare steel. Furthermore, the addition of a physical barrier will add another approach to the corrosion control actions used in the RC elements and infrastructure in general. There have been attempts in which either one of the corrosion control action have been used but not as integration or balance between them at the same time. A collaborative research study is proposed to investigate the medium and long-term durability of RC system by using different control actions and optimize the materials design for transportation infrastructure in Region 6. As a part of the integral study, performance tests under corrosive environment are to be conducted on different control action systems over different periods of time. Both material characterization studies related to laboratory and field conditions will be carried out as a part of this effort. Field conditions will illustrate and correlate the results founded in laboratory scale conditions. It is apparent that DOT can benefit greatly if a research project is undertaken to develop effective corrosion control methods. The proposed study and the design guidelines for hybrid or integrated systems would be beneficial to all state DOTs within the Tran-SET membership, as it will provide new approach for eco-friendly and corrosion resistant materials used for transportation infrastructure in Region 6. The proposed research with hybrid protection mechanisms (HPM), should provide a sustainable and alternative technology applicable to the existing RC infrastructures to increase their life cycle. Therefore, the proposed collaborative study focuses on these Tran-SET’s areas: Area 4: Improving durability and extending the life of the infrastructure (Sub-area: Application of new materials and technologies); Area 6: Preserving the existing transportation system. Two doctoral students will work with PIs in the execution of the proposed research tasks. The expected deliverable from this project is a technical report summarizing all tasks from both institutions, including necessary design guidelines of HPM. Results of this project will be also disseminated in related workshops and conferences, and presented to the industrial partners.