Volume 28, Issue 3 (May 2000)
Network-Level Pavement Deflection Testing and Structural Evaluation
Structural evaluation provides valuable information about the expected behavior of pavements and can be very useful at the network level of pavement management for project prioritization purposes. However, due to the expense involved in data collection and analysis, structural capacity is usually not determined at the network level. In Kansas, due to limited resources and the large size of the network (10 971 miles), annual network-level structural data collection at the same rate (five to ten tests per mile) as the project level is not realistic. This study was initiated to determine the sample size (% mileage) at the network level as well as the test intervals and frequency that can be used as guides for network-level deflection testing and structural evaluation of pavements.
Falling-weight deflectometer (FWD) data, collected on 571 km (357 miles) of non-interstate asphalt pavements of the Kansas Department of Transportation from 1993 to 1996, were used in the analysis. Three response variables were studied: (1) normalized and temperature-corrected first sensor deflection, (2) backcalculated subgrade resilient modulus (Mr), and (3) effective pavement modulus (Ep). Statistical analysis of these variables showed that the FWD tests up to a three-year interval at the network level yield statistically similar pavement responses and layer properties. At the network level, FWD tests on 20% mileage appear to be a valid statistical choice, and three tests per mile is the minimum test frequency required. An analysis procedure for assessing structural deterioration of pavements at the network level is also demonstrated.