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Federal Highway Administration Research and Technology
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Publication Number: FHWA-RD-02-085
Date: July 2006
Highway Concrete Technology Development and Testing Volume IV:Field Evaluation of SHRP C-206 Test Sites (Early Opening of Full-Depth Pavement Repairs)
CHAPTER 4. CONCLUSIONS AND RECOMMENDATIONS
The full-depth repairs made with HES materials placed under SHRP C-206 gave variable long-term performance. All sections in Georgia provided excellent performance; however, the performance of the Ohio sections was plagued by the longitudinal cracking that developed in a majority of the repairs within few weeks after the repairs were opened to traffic. An analysis conducted under this study showed that the most likely cause of the longitudinal cracking in the Ohio sections is the excessive difference between the PCC temperature during curing and the nighttime low temperatures. Two of the Ohio sections (VES and FS) also started to develop map cracking by 1997. These two sections developed extremely high temperatures during curing (excess of 70 °C); DEF is the suspect cause of the map cracking.
The following conclusions can be made based on the performance of the full-depth repairs at the two SHRP C-206 test sites:
The results of this evaluation showed that in terms of fatigue damage or faulting performance, the repairs could be opened to traffic at much lower strengths than those typically recommended. However, opening at strengths much less than those recommended in various manuals of practice (ACPA 1995; Yu et al., 1994; Snyder et al., 1989) is not advisable because of the risk of random failures caused by a single heavy load at an early age. Therefore, the following opening criteria suggested in the SHRP C-206 manual of practice are still recommended:
No change is recommended to the minimum repair size, but further research is recommended into the effects of repair size on potential for longitudinal cracking. The Ohio site where the longitudinal cracking was a problem only had 1.8-m repairs. Therefore, the effects of repair size could not be determined. Although the temperature conditions during construction appear to be the dominant factor affecting the risk of longitudinal cracking, it is possible for repair dimension to be a factor.