COST 351 - WATMOVE - Water Movements in Road Pavements and Embankments
Overview
Background & policy context:
Many billions of EUROs are spent on road construction and maintenance each year, and road transport is the primary method of mobility for European people and goods. Transport constitutes about 10 % of the Gross National Product of the European Union and more than 80 % of the total transport of people and goods is provided by the road infrastructure. Investment in road construction and maintenance in Europe is therefore at a very high level and any improvements can have a significant effect on the overall cost benefit ratio.
In many countries premature break down of especially low volume asphalt roads is an accelerating problem. The origin is usually increasing traffic, higher axle loads and an increasing use of super single tires, but also distresses like rutting and cracking caused by heavy traffic under the influence of climate and thermal movements. Water in pavements and embankments plays a primarily role giving shorter service life of pavements and increasing the need of rehabilitation measures. A further problem that is becoming of more and more concern, is the possibility that the road is a source of contaminants that are having an undesirable effect on the hydrological environment. Two sources are possible: leaching of contaminants from the road construction materials and earthworks; contaminant in runoff from rainwater or snowmelt that flows over the top of the pavement and then soaks into the ground.
The resources for maintenance works are limited and often not sufficient to keep the roads in a proper condition. Much work therefore is needed to develop new cost effective maintenance methods. The activities within this COST Action face the problem of transport system efficiency, developing new knowledge about water movement in pavements and creating a more efficient methodology of road construction and rehabilitation.
Objectives:
The main objective of the Action is to increase the knowledge required for improving the highway performance and minimising the leaching of contaminants from roads and traffic.
Improvement of pavement performance will lead to less road closures, better use of the road network, longer service life and more effective transportation of goods and people.
The aim of the Action can further be divided into the following four secondary objectives:
- to identify water movement and moisture conditions in unbound pavement layers and subgrade for different types of road constructions in various climatic conditions,
- to investigate the relationship between the mechanical behaviour of materials/soils and their hydraulic conductivity and moisture condition,
- to implement finite element modelling based on laboratory analysis and field studies in order to simulate water movement and moisture conditions in road construction,
- to identify, investigate and control contaminants leaching from soils, natural aggregates and by-products.
Besides these technical objectives, the Action's results will contribute also to the environmental and road safety improvement.
Methodology:
The work has been organised in the following activities.
- State-of-the-art. Activities were carried out to do a Literature review on:
- observations and results obtained in laboratory experiments and field investigations;
- tests and use of models for prediction and design purposes.
- Modelling and Monitoring of water flow and moisture within pavements and subgrades. A review and survey of existing models was carried out as well as evaluation of models appropriate for hydrogeological considerations related to highway design. Parameters for models are important and need to be investigated. Furthermore there was an inventory and survey of technologies for measurements of water movement and moisture content in roads with various materials and pavement structures.
- Environmental aspects of water in roads. A review and classification of pollutants leaching from road construction materials was done. Furthermore, mechanisms and factors affecting the leaching and transport of pollutants were studied and finally a review and evaluation of remedial measures was given. This included an inventory of methods for handling and treatment of highway drainage.
- Discussion of performance-related properties. This included an inventory and survey of water related factors relevant for an appropriate pavement performance. Both bearing capacity and frost actions were studied and related to the moisture content of the pavement structures. Included in the investigations were moisture versus compaction and moisture versus fines (plasticity, type etc.). Finally a review and investigation of relationships between laboratory and field analysis was given.
- Formalisation of results. Activities were carried out to produce the Final Report that draws together the essence of all activities carried out during the project. It summarises, draws conclusions, puts forward recommendations, and sets programmes for disseminating the work of the Action.
Share this page