2011 - Ireland - Pavement Deterioration Modelling Assessment

Interesting paper comparing Ireland's PMS models with HDM, and New Zealand's experieinces.

Ireland has a national road network of approximately 5300km which is managed by Transport Infrastructure Ireland (TII). TII create yearly pavement maintenance and renewal programmes using a Pavement Asset Management System (PAMS). Accurate pavement deterioration models and reset values are an essential part of a PAMS and are required for life cycle cost analysis (LCCA). Pavement maintenance and renewal schemes are prioritised based on the LCCA's largest benefit to cost ratio, thereby optimising the annual pavement maintenance and renewal budget. Currently, TII implement pavement deterioration models based on models used in Austria and Belgium, with modifications appropriate to Irish conditions. The reset values in use are based on best estimates of expected treatment effects and were not initially based on the measured post-treatment condition. This research aims to refine and improve the deterioration models currently in use and to calibrate the treatment reset values using measured pavement condition on treated sections of pavement. Several long-term pavement performance (LTPP) monitoring sites were selected for the analysis. The LTPP monitoring sites consist of newly constructed and recently maintained pavement sections throughout the Irish national road network for each subnet category. The international roughness index (IRI), rut depth and longitudinal profile variance 3m (LPV3), measured annually from 2010 to 2019, were analysed and compared to the current PAMS's pavement reset values and deterioration models. Generally, the measured reset values of the LTPP monitoring sites were lower than the TII's PAMS reset values, indicating that TII's PAMS may underestimate the treatment benefit for the LCCA treatment prioritisation process. The measured pavement deterioration rates were also typically lower than the predicted pavement condition values of TII's PAMS. This research concludes that an update to the PAMS, using better calibrated deterioration models and reset values would be highly beneficial. The LTPP monitoring should be continued to assess the longevity of the applied pavement treatments and consequently, determine the full deterioration model for each of the LTPP monitoring sites into the future.