Prediction of asphaltic overlay thickness for rehabilitating flexible pavement using Empirical-Markovian approach

Abstract

This paper presents a simplified Empirical-Markovian approach for estimating the asphaltic overlay thickness used in rehabilitating flexible pavement at the project level. The main element of the proposed Empirical-Markovian approach is the prediction of the future pavement conditions which are estimated using the heterogeneous discrete-time Markov model. The required heterogeneous transition probabilities are predicted for an original pavement structure by mainly relying on the first-year transition probabilities. The empirical overlay design model is developed assuming both original and overlaid pavements will exhibit similar performance trends over time as represented by the corresponding performances curves. This has been accomplished by requiring the deterioration transition probabilities associated with both pavements to be equal in values. The overlay model developed is mainly a function of the annual traffic growth rate, rehabilitation scheduling time, initial structural capacity associated with original pavement, and two calibration constants. The two calibration constants are the same ones obtained from the development of the empirical model used to estimate the heterogeneous transition probabilities associated with original pavement. A sample problem is presented to illustrate the use of the proposed overlay design model. The sample overlay design thicknesses predicted for variable rehabilitation scheduling time appear to be reasonable and consistent with the general practice.