REHABILITATION PROCEDURES FOR FAULTED RIGID PAVEMENT

Faulting of transverse joints in rigid pavements generally has not been a problem in New York, but a change in load-transfer devices (LTDs) between 1960 and 1972 produced significant faulting in pavements with high-volume truck traffic. The results of an 8-year study conducted on Interstate 84 are described. Constructed in the late 1960s, I-84 is a four-lane, 23-cm-thick concrete highway with 18.55-m joint spacing. As a result of failure of LTDs and heavy commercial traffic, faulting became a significant problem in the 1970s. In 1980 a study was begun to determine the most efficient method of removing the faults. After the first 2 years of field study, it was determined that where truck traffic is heavy, it is absolutely necessary to restore load-transfer capability with retrofitted LTDs to minimize pumping and loss of support that result in faulting. In 1983 the study was extended to establish criteria for effective procedures of fault removal and load-transfer restoration. By 1985 the magnitude of faulting at joints not retrofitted was already as great as when faults had been corrected. A second phase of the study thus was initiated to evaluate the effectiveness of LTD replacement in keeping faults from recurring. Two LTDs--the University of Illinois retrofit (the double-V device) and I-beam dowel bars--were installed from 1982 to 1985, retrofitting 289 joints at various locations on I-84. Their performance was evaluated by comparing (a) the rate of faulting return, (b) magnitude of differential joint movement, and (c) distress indexes. Construction and field testing of the LTDs are described, and their effectiveness in removing faulting and restoring load transfer is compared. From the findings, rehabilitation strategies are suggested.