Predicting In-Service Performance of Flexible Pavements from Accelerated Pavement Test – Fatigue Performance
The University of Texas, ECJ 6.508, Austin, TX 78712-0278
Tel.: (512) 471-8270, Fax: (512) 475-8744,
There are a wide variety of APT programs under operation in the world today. Till 2004, twenty-eight such programs were reported as being currently active, among which 15 are in the United States. APT programs have led to advances in practice and economic savings from the evaluation of new pavement configurations, tire, tire pressure and wheel arrangements, new materials and design improvements. However, because of the limited ability to address long-term phenomena, the same pavement structure may exhibit different response and performance under APT than when in-service. Therefore, to fully utilize the benefits of APT, there is a need for a methodology to predict the long-term performance of in-service pavement structures from the results of APT tests which will take account of such differences (NCHRP10-66). Three models are generally suggested to account for the difference, which are shift factors, statistical and mechanistic.
A reliability based methodology for fatigue cracking prediction is developed in this study. Through which the three models suggested previous are combined into one general approach that builds up on their individual strengths to overcome some of the shortcomings when the models are applied individually. The unobserved differences and other differences of secondary order effect will be considered part of the model error.
The bias correction factor or bias correction function should account for all quantifiable differences between the performance of the pavement section under APT and in-service conditions. Lab tests will be carried out as required to quantify special aspect difference.
PRESENTER'S QUESTIONS: I would like to receive comments, suggestions, and feedback from the meeting's attendees on the following matters:
APT programs under operation in the world today
Bias correction factor for aging problems
Application of reliability based methodology
PRESENTER'S STATEMENT: This work is still in progress, and has not been submitted for presentation or publication at another meeting.