Cracking models for use in pavement maintenance management

With the recent approval of the Portuguese Law No. 110/2009 of 18 May, within the scope of road concession contracts, the concessionaires need to submit to the Portuguese Road Infrastructures Institute a Quality Control Plan (QCP) and a Maintenance and Operation Manual (MOM). These documents require the revision of current Pavement Management Systems to consider pavement performance prediction models for each pavement state parameter so that it permits time definition of maintenance and rehabilitation (M&R) interventions for the fulfilment of the values defined in the QCP in each year of the concession period. The QCP presents the admissible values for each pavement state parameter (cracking, rutting, roughness, etc.) that a concessionaire of highways needs to verify. Nevertheless, a concessionaire, beyond the annual pavement inspections to demonstrate the fulfilment of the QCP, wants to predict the proper time to apply M&R preventive interventions at a minimum cost for the complete concession period. This paper describes the state-of-the-art in terms of cracking models. The selected models evaluate the cracking area evolution for a set of representative Portuguese pavements structures and traffic conditions. The Indian and HDM-4 deterioration models were considered to be the most promising to implement in a new Portuguese Maintenance Optimisation System, i.e. to provide a good solution to the pavement maintenance management problem involving not only periodic maintenance but also routine maintenance (crack sealing, rut levelling, patching, etc.).