Among various sectors, the transportation infrastructure especially the reinforced concrete pavements (RCPs) and bridge decks are severely affected by corrosion. The corrosion of steel rebars in the RCPs and bridge decks severely deteriorate their functionality and thus require frequent maintenance and replacement of components that result in traffic congestion, and road closures. The costly maintenance and the resulting traffic delays result in huge cumulative losses each year. Americans lost 6.9 billion hours and 3.1 billion gallons of fuel due to traffic delays resulting in a cumulative loss of $160 billion in 2014 alone [1]. To address the corrosion issue in RCPs and bridge decks, this project aims at developing a novel Soy-protein ionic liquid based coating material for steel rebars embedded in RCPs and bridge decks that will significantly reduce the maintenance costs of RCPs and bridge decks by mitigating corrosion damage in the embedded rebars. To achieve the objectives of this project, ionic liquid soy-protein based coatings will be synthesized and their corrosion mitigation performance will be evaluated for embedded rebars. The low-cost and non-toxic Soy-protein based coating material that will be developed through the proposed research has the potential to provide substantial financial benefit to the North Dakota soybean farming community and curtail the cost of corrosion-related repair and maintenance in transportation infrastructure.

1) to synthesize an ionic Soy-protein liquid based coating material, and
2) to characterize the corrosion inhibition performance of the synthesized Soy-protein ionic liquid coatings embedded steel rebars.

1) Procedure for the synthesis of Soy-protein ionic liquid based coating
2) Characterization of the corrosion inhibition potential of Soy-protein ionic liquid based coatings for embedded steel rebars.
3) Semi-annual and annual final report for communicating the progress of the project.

Updated June 30, 2021:

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Updated July 10, 2021:

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Executive Summary
Project: Ionic Liquid Soy-protein based Coating for Protection against Chloride-ion Attack

Research conducted
Corrosion is a major form of deterioration that affects the service life and functionality of reinforced concrete structures such as bridge decks and reinforced concrete pavements (RCPs). In this study, a new low-cost and non-toxic protective coating material is synthesized from soy protein isolate (protein-rich component of soybean) for mitigating corrosion in RCP and bridge decks. The corrosion protection performance of the soy-derived coating material was evaluated through laboratory experiments. This soy-derived coating material can be applied on concrete rebars in the field. It can also be applied on cracked reinforced concrete surfaces to restrict further corrosion.

Why the research is important to ND soybean farmers
The global market for corrosion protection products (corrosion inhibitors) was estimated to be $7.2 billion in 2018 and it is projected to reach $9.2 billion in 2026. The soy-derived coating developed in this study has the potential to take advantage of this growth to financially benefit the ND soybean farming community. Even if only 1% of soybean products by weight is used for making the envisaged coating material, this will generate new demand for at least 1 million metric tons of soybeans which roughly translates into $300-350 million of additional revenue to the ND soybean farming community.

Final findings of the research
The results obtained from the laboratory investigations showed that soy-derived coatings are effective in protecting reinforcing bars from corrosion. The corrosion protection performance of the soy-derived coatings was validated through short-term and long-term laboratory tests. It was observed that the application of soy protein coatings can reduce the corrosion in reinforcing bars by up to 90% when compared to the reinforcing bars with no coating. The soy-derived coating materials are observed to have adequate adhesion for application on the steel surface. It was also observed that the soy-derived coatings have adequate strength and can be conveniently handled and transported to the field.

Benefits/Recommendations to North Dakota soybean farmers and industry
The soy protein coatings developed in this study can significantly expand the utilization of soybean products in a new industry (corrosion protection) and hence can increase the profitability of soybean production. Moreover, this work will also attract the attention of the industry to develop more value-added products from soybean.

The global corrosion inhibitor market size was around $7.2 billion in 2018 and is expected to reach $9.6 billion by 2026 with maximum investment growth coming from the construction industry [2]. The novel coating material that will be developed through the proposed research has the potential to take advantage of this growth to financially benefit the ND soybean farming community. On average, the US consumes 100 million and 6.5 million metric tons of concrete and steel, respectively every year for infrastructural needs and a substantial fraction of this is used for the construction and replacement of RCPs. Even if only 1% of soybean products by weight is used for making the envisaged coating material, this will generate new demand for at least 1 million metric tons of soybeans which roughly translates into $300-350 million of additional revenue to the soybean farming community. Besides this, the envisaged products have the potential to substantially curtail billions of dollars lost due to the repair, maintenance, and closure of concrete pavements and bridge decks in the U.S.