Published Online: 4 January 2008
Page Count: 10
Chen, Dar Hao
Ph.D., P.E. ProfessorPavement Engineering Supervisor, Changsha University of Science & Technology, ChangshaAustin, HunanTX
Ph.D., P.E., Research Associate Professor, University of Texas at Austin,
(Received 22 July 2007; accepted 28 November 2007)
This paper presents the performance of three rehabilitation methods on six highways to restore the condition of concrete pavement: (1) polyurethane foam injection (PFI), (2) dowel bar retrofit (DBR), and (3) full depth repair (FDR). PFI was able to raise the slabs to the target levels; however, it was not able to maintain the slabs at the target levels and thus prevent slabs from further settlement. In addition, new cracks have been observed in some slabs and it was believed that PFI might have created uneven supports that allowed the truck traffic to shatter the slabs. Long-term benefits of DBR were demonstrated on a project with 10 years of traffic, where asphalt overlay was placed. Only minimum reflective cracks were observed on the DBR sections as compared to severe reflective cracks on sections without DBR. In another project, DBR effectively restored the ride quality that reduced the International Roughness Index (IRI) from 2.83 m/km to 1.26 m/km. The poor ride of this pavement section before DBR was due mainly to severe faulting. This illustrates that dowel bars provided excellent load transfer at transverse contraction joints, which minimized the potential for faulting. FDR has been used to repair localized pavement distresses. However, subsidence of slabs and cracks reappeared on the slabs that received FDR, due partly to the inadequate base support. Currently, there are no objective test methods and criteria for base preparation in the FDR specifications. To improve the effectiveness of FDR, current FDR specifications need to be revised.
Paper ID: JTE101362