The objective of this project is to conduct a national effort that includes a series of regional workshops, an equipment loan program, and technical support in order to evaluate, showcase, and promote the use of SHRP products for assessing the physical condition of reinforced concrete bridge components.

Deterioration of reinforced concrete by corrosion of the reinforcing steel is the single most frequent cause of maintenance, rehabilitation, or replacement of reinforced concrete structural elements. The ability to identify an active corrosion process in the early stages is an important factor in minimizing the cost of corrosion related repairs. The SHRP study identified several viable techniques that could be combined with the existing technology to provide a "toolbox" for an integrated approach to the condition assessment of reinforced concrete bridges.

The selection of techniques and procedures for application is based on several criteria. Most important is the ability of the method to carry out the required function at an acceptable performance level. Simplicity of operation is another important criterion, and the technology must also be field-ready, rugged, and possess a high degree of reliability.

A number of preliminary recommendations have been established:

• Delamination Detection: Sounding of concrete surfaces is recommended. Methods using stress waves may be economical if used concurrently to detect other types of damage or deterioration.
• Corrosion Detection Halfcell potential measurement is recommended.
• Structural Damage Stress wave (impactecho and pulse velocity) methods are recommended.
• Reinforcing Cover and Location Magnetic flux methods are recommended.
• Deteriorated Concrete and Voids Stress wave methods are recommended.
• Moisture Content Neutron methods are recommended.
• Strength Assessment Rebound Hammer or penetration methods, backed up by compressive strength of drilled cores, are recommended.
• Prestressed and PostTensioned Structures At this time, only visual methods can be recommended and no quantitative methods are field-ready.
• Petrography: This is recommended only when conditions related to concrete quality are involved and data cannot be obtained by any other method.

The contract for this Showcase project was awarded to Concorr Inc. on August 3, 1994. Showcase presentations are currently being conducted.

Showcase workshops on assessment of physical condition of reinforced concrete structures.

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HIGHWAYTECHNET   VIRTUAL EXPO   STRUCTURES INDEX

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U.S. Department of Transportation
Federal Highway Administration