Quantifying the Relationship between Mechanisms of Failure and the Deterioration of CRCP under APT: Cointegration of Non-stationary Time Series

Abstract

A statistical property of non-stationary time series is applied to quantify the long-run equilibrium relationship between mechanisms of pavement failure and deterioration. The concept is applied to measured pavement responses from an Accelerated Pavement Test (APT) conducted on the thin (185 mm) Continuously Reinforced Concrete Pavement (CRCP) of the Ben Schoeman freeway in South Africa. The statistical property is that of cointegration, which allows testing for the existence of equilibrium relationships among trending variables within fullydynamic specification frameworks. The predominant failure mechanisms leading to punchout are known to be loss of load transfer capability at transverse cracks and the deterioration of substructure support. The long-term relationship between proxy variables for the mechanisms leading to punchout and pavement deterioration is determined. The average long-term relationship between a change in relative movement and a change in surface deflection at transverse cracks is found to be 17.5. This means that on average a 1.0 % increase in relative movement will translate into a 17.5 % increase in surface deflection and vice versa. The empirical quantification of the long-term equilibrium relationships between pavement mechanisms of failure and deterioration offers the potential to improve the reliability of design systems and may also be used in pavement management.