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Concrete overlays were placed on continuously reinforced concrete (CRC) pavement sections of I-295 near Richmond, Virginia, and I-85 near Petersburg, Virginia. A 2-in. bonded portland cement concrete overlay on I-295 was placed to prevent spalling attributable to improper steel depth of the existing CRC pavement, and a 4-in. bonded portland cement concrete overlay on I-85 was placed to increase the structural capacity of the pavement. The CRC pavements were in reasonably good condition when the overlays were placed. Evaluations of the bonded overlays were conducted immediately after their placement in 1995, in 1999, and in 2006 after 11 years in service. The evaluations included bond strength testing between the overlay and the CRC pavement, chain drag testing to detect delamination between the overlays and the pavement, falling weight deflectometer testing to assess the in situ structural capacity of the bonded overlay pavement sections, permeability testing to determine the permeability conditions of the overlays, and skid resistance testing to check the surface texture conditions. The bonded concrete overlays performed well after 4 and 11 years. The results indicate that bonded overlays extended the life of the existing CRC pavements and are expected to last 20 years or more. The experience gained during 11 years is documented and the use of bonded concrete overlays is recommended where the design life can be realized.

Shrinkage performance was examined of Virginia Department of Transportation-approved latex-modified and microsilica concrete overlay mixtures. Research was conducted on both field-sampled and laboratory-fabricated restrained and unrestrained specimens. From crack and delamination surveys of sampled bridge decks and laboratory test results, a shrinkage performance-based specification for the Virginia Department of Transportation was developed. There was no significant difference between the unrestrained shrinkage values of latex-modified and microsilica concrete overlay mixtures for the specified time periods. Restrained microsilica concrete specimens generally cracked earlier and more frequently than restrained latex-modified concrete specimens. However, the bridge deck crack and delamination surveys show that conditions and quality of construction and type and frequency of traffic may have a greater effect on cracking than the overlay material.

During its service life, concrete experiences volume changes. One of the types of deformation experienced by concrete is shrinkage. There are four main types of shrinkage associated with concrete: plastic, autogenous, carbonation, and drying shrinkage. The volume changes in concrete from shrinkage can lead to the cracking of the concrete. In the case of reinforced concrete, cracks in the cover concrete provide a direct path for chloride ions to reach and corrode the reinforcing steel. The development of concrete drying-shrinkage performance specifications with an associated test procedure was assessed for concrete mixtures purchased by the Virginia Department of Transportation (VDOT). Five existing shrinkage-prediction models were also assessed to determine the accuracy and precision of each model as it pertains to the VDOT mixtures used in this study. The five models are the ACI 209 Code model, CEB90 Code model, Bazant B3 model, Gardner–Lockman model, and Sakata model. The percentage length change limits for the portland cement concrete mixtures were found to be 0.0300% at 28 days and 0.0400% at 90 days. The CEB90 Code model was judged as the best prediction model for the VDOT portland cement concrete mixtures.