Chapter 1

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The objective of this study was to monitor and evaluate the performance of experimental full-depth repairs made with high-early-strength (HES) materials placed under Strategic Highway Research Program (SHRP) project C-206, Optimization of Highway Concrete Technology (Whiting et al. 1994). The C-206 full-depth repair experiment was conducted to demonstrate and validate the technologies that allow early opening of full-depth portland cement concrete (PCC) pavement repairs to traffic and to document the information needed to apply this technology.

The experimental factors for the full-depth repair experiment included material type, strength at opening, and repair length. A total of 11 different HES concrete mixes with opening times ranging from 2 to 24 hours (hr) were evaluated at 2 field sites (U.S. Interstate 20 (I-20), Augusta, GA and State Route 2, Vermilion, OH). The repair materials included various HES PCC mixes made with Type I and Type III portland cement and mixes made with proprietary blended cements. The repair lengths ranged from 1.8 to 4.6 meters (m). A test section in this experiment consists of uniform-size repairs made with a single material. The repairs were made over a range of time and opened to traffic simultaneously when the last repair reached the target strength, which provided a range-of-strength at opening.

One of the goals of the SHRP C-206 full-depth repair experiment was to establish guidelines for the minimum strength required at opening time to ensure adequate performance of full-depth PCC pavement repairs. Based on analytical results, guidelines for early opening of full-depth PCC pavement repairs were developed under SHRP C-206 and incorporated in the manual of practice that was developed under that project (Yu et al., 1994). However, long-term monitoring was needed to verify the guidelines developed under SHRP C-206—that task was carried out under this study.

The scope of this study included 5-year monitoring of SHRP C-206 full-depth experiment sections, analyzing the data, and revising guidelines for early opening of full-depth PCC pavement repairs as needed. The monitoring program consisted of annual visual distress surveys to monitor the development of the following:

• Cracking.
• Faulting.
• Spalling.

The annual surveys were conducted from the fall of 1994 through the fall of 1998. At the Georgia site, deflection testing was also conducted in 1996 using a Falling Weight Deflectometer (FWD) as a nondestructive means of evaluating long-term repair material properties and to evaluate load-transfer efficiency (LTE) across repair joints. The deflection testing was not conducted at the Ohio site because most of the repairs at the Ohio site contained a longitudinal crack, and all of the repairs at this site are 1.8 m long, which is too short to obtain good backcalculation results, especially with the presence of the longitudinal crack.

This report presents the results of annual surveys and analysis of the collected data. The report for each site begins with a brief description of the field sections (full detail of the experiment is provided in Whiting et al., 1994), followed by a discussion of performance of test sections. Finally, conclusions and recommendations for possible changes to fast-track full-depth repair practice are provided based on findings of this study. A summary of the results of annual condition survey is provided in appendix A. Appendix B provides summary tables of the data collected for all sections.