Title: INTERPRETATION OF BACKCALCULATED LAYER MODULI OF CRACK-AND-SEAT PAVEMENT FROM FALLING WEIGHT DEFLECTOMETER DATA
Abstract: In 1986 the Arizona Department of Transportation rehabilitated a section of Interstate 40 using a crack-and-seat technique. The project, in north-central Arizona, consisted of cracking the existing jointed plain concrete pavement in a 3- x 3-ft pattern and seating these areas before placing a 4-in. asphalt concrete overlay. Two test sections, each 0.1-mi long, were constructed on the project. One of these test sections used a nominal crack spacing of 4- x 6-ft, and the other a spacing of 2- x 2-ft to investigate the effect of crack spacing on the performance of this project. To establish the changes in effective modulus of cracked portland cement concrete (PCC), falling weight deflectometer (FWD) testing was conducted for 5 years after construction. Layer moduli were backcalculated from the FWD deflection test results using an elastic layer analysis program. The structural layer coefficients for the cracked PCC layer were analyzed to establish a difference in structural characteristics of sections with various crack spacings. Large variations in the effective modulus of the cracked PCC layer were obtained from the backcalculation technique. Unreasonably high moduli were computed through this process. The backcalculated concrete moduli tended to fluctuate over time, but no definite trends were established. The structural layer coefficients of the cracked PCC layer were also analyzed. This analysis showed that there is no remarkable difference in structural response of cracked and seated concrete pavement corresponding to various crack spacings.
Publication Year: 1992
Publication Date: 1992-01-01
Language: en
Type: article
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Cited By Count: 2
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