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South Dakota Department of Transportation
Project Synopsis

Title: Evaluation of Metallized Stainless Steel Clad Reinforcement
Project Researcher: David Darwin, The Universtiy of Kansas
Project Manager: Dan Johnston
Research Period: 10/1/2002 - 5/31/2007
Cost: $0.00

Problem Statement:The ongoing problem of corrosion of reinforcing steel in bridge decks has been addressed in South Dakota with increased concrete cover over reinforcement and the use of epoxy-coated rebar (ECR). To date, these measures appear to have worked well extending bridge deck life significantly. With the development of new materials and technologies, there maybe a potential for increasing deck life and/or reducing the amount of concrete cover on bridge decks. One of these new materials is a 316L stainless steel clad reinforcement manufactured by using a metallizing technique called the Osprey Process. This clad steel may be much less susceptible to corrosion than black steel or ECR, and may provide the means of preventing corrosion caused by deicing salts from occurring throughout the life of a structure.

The purpose of this research is to evaluate the potential corrosion resistance, mechanical properties and uniformity of the SMI-316 SCÔ using laboratory tests. Based on the results of these tests, South Dakota Department of Transportation (SDDOT) may design, construct and evaluate a bridge deck reinforced with this Corrosion-Resistant Steel. All test results will be compared with those from epoxy-coated reinforcement and mild steel using the same protocols developed in SD2001-05 Evaluation of Corrosion-Resistant Reinforcing Steel. The research will provide information on the constructability and effectiveness of this Corrosion-Resistant Steel for use in bridge decks as well as performance, service life and cost-effectiveness data.

Findings: SMI-316 SC stainless steel clad reinforcement is recommended as a cost-effective direct replacement for epoxy-coated reinforcement. Cut ends of the bars should be protected with a system such as plastic caps filled with epoxy and the bars should be protected from damage to the cladding during bending operations. MMFX Microcomposite reinforcing steel should not be used as a direct replacement for epoxy-coated reinforcement without the use of a supplementary corrosion protection system. Use of the material in its current form is not recommended for reinforced concrete bridge decks in South Dakota.

Research Objectives:
1  Determine the corrosion-resistance of the SMI-316 SCÔ compared to ECR reinforcement.
2  Determine the mechanical properties, quality and suitability of the SMI-316 SCÔ for use in bridge decks.
3  Estimate life expectancy and cost effectiveness of the SMI-316 SCÔ, ECR and mild steel reinforcement in South Dakota.

Research Tasks:
1  Perform a literature search on the SMI-316 SCÔ and its use as reinforcement including a survey of any identified users.
2  Conduct a series of laboratory tests consisting at a minimum of elongation, yield strength, tensile strength, ASTM bend properties, composition, and corrosion rate on #4, #5, and #6 SMI-316 SCÔ, and mild steel including end treatment effectiveness an
3  Provide evaluation of cladding uniformity, thickness variability, effects due to deformation profile and bond with the base metal on #4, #5 and #6 reinforcement.
4  Conduct a series of statistically valid comparative tests of corrosion resistance on the SMI-316 SCÔ, ECR and mild steel reinforcement to determine general corrosion properties both inside and outside concrete, stress and pitting corrosion properties
5  Analyze corrosion effects on the SMI-316 SCÔ using scanning electron microscopy.
6  Submit an interim report no later than November 30, 2002 estimating SMI-316 SCÔ service life and providing a recommendation of whether SMI-316 SCÔ should be incorporated into a bridge deck including any necessary modifications to design or constructi
7  Estimate life expectancy and cost effectiveness of the SMI-316 SCÔ, ECR and mild steel reinforcement in South Dakota.
8  Prepare a final report and executive summary of the literature review, research methodology, findings, conclusions, estimated life for each steel type, evaluation plan and recommendations.
9  Make an executive presentation to the SDDOT Research Review Board at the conclusion of the project.
10  Compare the corrosion potential of conventional and MMFX Microcomposite steel in simulated concrete pore solution at NaCl molal ion concentrations ranging from 0.4 to 6.04.
11  Determine the chloride content at the corrosion threshold for conventional and MMFX Microcomposite steel.
12  Use the new data to modify life expectancy and cost effectiveness calculations for bridge decks containing MMFX Microcomposite steel.

Documents Available:

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