WTI

Validating the Durability of Corrosion Resistant Mineral Admixture Concrete - UTC

Primary Investigator Contact Information

External Project Contact(s)

Report(s)

There are no reports associated with this project.

Project Objective

The objectives of this research are to validate chloride diffusion coefficients of mineral admixture concrete mix designs currently developed by departments of transportation (DOTs) for corrosion mitigation, and to verify the adequacy of existing measures to mitigate corrosion caused by exposure to marine environments and deicing salt applications.

Project Abstract

Chloride-induced corrosion of reinforcing steel in concrete is a major issue for the service life and reliability of concrete structures and has been estimated to cost U.S. transportation agencies approximately five billons dollar a year. Once corrosion begins, it can propogate and deteriorate the concrete in only a few years. Therefore, to increase the durability of concrete, it is critical to prolong the initiation stage, which is a function of the chloride transport properties of concrete (usually the diffusion coefficient), the surface chloride content dictated by the environment, the concrete cover thickness, and the chloride threshold concentration determining the onset of active corrosion. State departments of transportation (DOTs) have developed concrete mixes for corrosion mitigation of bridge structures, and mineral admixtures have been used to reduce the permeability of concrete to chlorides while keeping the concrete cover requirements at reasonable thicknesses. Current test methods, however, do not provide consistent or expedient methods for evaluating different concrete mixes and admixtures. The objectives of this research are to validate chloride diffusion coefficients of mineral admixture concrete mix designs currently developed for corrosion mitigation, and to verify the adequacy of existing measures to mitigate corrosion caused by exposure to marine environments and deicing salt applications. The project will develop and establish standard, accelerated test methods to determine the chloride diffusion coefficient and chloride depassivation thresholds of conventional and mineral admixture concrete specimens, as well as a model for calculating projected service life of steel-reinforced concrete structures.

Task Descriptions

1. Project Management
   1. This task covers project management activities throughout the duration of the project, including budget and staff management, communication and outreach, and preparation of deliverables.
2. Literature Review
   1. Using academic journals, government publications, and a detailed Internet search, the research team will conduct a comprehensive literature review to further investigate existing research related to this project, including durability of mineral admixture concretes, methods of determining chloride diffusion coefficients of concrete, modeling of chloride ion ingress in concrete, and assessment of the concrete durability from its permeation properties.
3. Laboratory Investigation
   1. The research team will design a series of experiments to study the influence of concrete mix design parameters on the resistance to chloride ingress and concrete durability. The team will use the experiments to evaluate 18 concrete mix designs, conducting the tests on custom-created concrete samples.
4. Service Life Modeling
   1. Using the findings from the lab experiments, researchers will develop a model to predict the service life of steel-reinforced concrete structures, which takes into account various concrete mix parameters.
5. Final Paper and Outreach
   1. The research team will prepare a final report summarizing the literature review, laboratory findings, and conclusions. Key findings from this report will be submitted for publication and/or presentation at conferences such as the Transportation Research Board (TRB) annual meeting.

Milestones, Dates, Schedule

Student Involvement

False

Relationship to Other Research Projects

False

Technology Transfer Activities

True

Transportation Research Board Keywords

Reinforced concrete, chloride-induced corrosion, chloride diffusion coefficient, concrete structure service life

Partners

Research and Innovative Technologies Administration, USDOT