Partner und Internationale Organisationen
(Englisch)
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LCPC, VTT, VTT, CROW, CEDEX, TRL
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Abstract
(Englisch)
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Road transport provides over 80 per cent of all transportation in Europe. A well maintained road infrastructure therefore is essential to Europe's economic development. Maintenance of the road infrastructure calls for structured planning, taking into account the life-cycle costs of the pavements and the consequences for the road users in terms of delays and safety at the road closures associated with the execution of maintenance. Such structured maintenance planning is conducted using pavement management systems, which are widely used in Europe within road authorities.
Key elements in pavement management systems are pavement deterioration models, which are used to forecast when a given road section reaches the maintenance intervention level for the pavement distresses considered. The PARIS project (Performance Analysis of Road Infrastructure) was aimed at developing robust pavement deterioration models for the European inference space of traffic loading and climate for flexible and semi-rigid pavements. The project duration was two years, from 1 October 1996 until 30 September 1998. Fifty per cent of the project funding was from the European Commission under the Transport Research and Technological Development Programme of the Fourth Framework Programme and the remainder was from the nineteen organisations from fifteen European countries participating in the project. The organisations provided historical distress data on selected pavement test sections from their road network, by performing data acquisition on those sections. Further they took part in the development of the pavement deterioration models and in the validation of those models.
The work on the project started with the Elaboration of Project Tasks. The basis for this work was laid in COST Action 324 'Long Term Performance of Road Pavements'. At the start of the project, the ambitions of the project were agreed by the Steering Committee which comprised representatives from all participating organisations, taking into account the resources available for the project. The two years duration of the project called for the use of historical data on pavement deterioration in the analysis, which was provided from data sources at the participating organisations. Such data were collected in so-called Real-Time Loading Testing on selected sections of the road network subjected to normal traffic loading. An assessment was made of these historical data sets, resulting in a set of over 700 test sections meeting the criteria for inclusion in the analysis to produce deterioration models. Additional sections were selected for the validation of the crack initiation model, bringing the total number of pavement test sections in the project to over 900.
The historical pavement condition data were collected within the participating European countries using national monitoring systems and therefore they needed to be normalised to a European standard prior to storage in the PARIS database and the subsequent analysis. The plan for developing the normalisation methodology involved site inspections in all the participating countries by an international team of experts.
The normalised historical distress data were augmented in the analysis by data gathered from measurements on the test sections in 1997 and 1998. The data acquisition activities and the storage of the resulting data in a specially developed database were planned in detail, taking into account the requirements of the analysis to follow. In that analysis, the data from the sections of the regular road network were augmented by data from past studies in Accelerated Loading Testing (ALT) of pavement structures, using dedicated facilities. These ALT data provided information on the functional forms of the models to be developed, covering the full range of deterioration from the onset of distress up to pavement failure.
Two types of deterioration models were produced in the analysis, being distress initiation models and distress propagation models. Distress initiation models enable the first appearance of distress to be predicted, whereas distress propagation models describe how the distress develops with time in both severity and extent. A distress initiation model for cracking and distress propagation models for cracking, rutting, longitudinal unevenness and ravelling were investigated.
An important aspect of the project was to check that the pavement deterioration models developed were applicable in other countries whose data were not used to develop the models. In order to check this, it was agreed in the initial project planning that distress data from four countries, whose data covered a shorter period of time than the data from the other eleven countries, would be used to validate the models for use in these countries.
The benefits from this study for the practitioners of pavement management are as follows. The models produced are suited for use in the daily practice of pavement management. They require only input parameters that are readily available to the pavement manager. Further, they describe the part of the distress evolution which is of relevance in the planning of pavement maintenance and rehabilitation. The distresses modelled are those which are essential for pavement management purposes. In all, the models presented in this report can help the pavement manager produce a system of prudent investment for his road network.
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