|
|
Pavements (Cluster 4)
Setting A group of European pavement specialists has investigated the possibility to reduce pavement thicknesses and develop an environmental friendly road. Based on a number of worldwide good experiences and test sections, a new performance based design method has been developed. Local available materials can be used in the base layer of the road, transport of building materials will thus be minimised. As a result CO2-emissions during construction are reduced, a contribution to Kyoto goals will be achieved. This new type of thin pavements is far cheaper than regular pavements. Objectives In most countries increasing traffic asks
for more and wider roads. This results in a large consumption of
high quality building materials. Production and transport of those
materials produces lots of CO2 with an adverse effect
on the environment. Therefore a new type of pavement is wanted which,
against competitive costs, reduces the impact on the environment. This cluster investigates the possibility to create cheaper environmental friendly roads. A project description can be found in the original project plan, a shorter version and presentation is also available. Compared to a 'conventional pavement' it should realise the following goals:
In every country it should be possible to
develop and design such a new 'ECOserve type pavement'. Environmental
indicators will be used during the development, they also will be
used to judge whether these goals are achieved. In this way the
work in Cluster 4 will support the EU policies; particularly its
environmental goals through the contribution to a sustainable construction
industry but also through its contribution to cost effective construction
methods. Cluster leader Robbert Naus
of Dutch based contractor Dura Vermeer is very positive about the
potency: 'If our approach works, it will be a revolution in pavement
design'. Worldwide there are some good experiences with semi-rigid pavements with a thin asphalt topping which last much longer than where they were designed for. In all European countries a lot of cement treated bases (CTB) are applied but each country has its own design method. To understand more about the different design methods a questionnaire was sent out to many countries to collect the different ways of designing semi-rigid pavements i.e. pavements with a CTB and an asphalt topping. It appeared that only very few references of semi-rigid pavements with a thin asphalt topping were mentioned. Above a certain compressive strength of the CTB precautions must be taken to control the cracking pattern. The response and conclusions of this collection of data is reported. Consequently a further investigation of some design methods and their differences is carried out and reported. The Danish members of the pavements cluster, Danish Road Institute, COWI and Dansk Beton Teknik, were involved in a DRI research program. The goal was to examine the behaviour of test sections of semi-rigid pavements with different types of base layers and develop a model to predict deterioration based on the results of FWD measurements. Although not part of ECOserve, this experiment perfectly fits in its ideas. Results can be viewed in the report published on the website of DRI. Based on the few good references and the DRI research program an incremental-recursive model was developed.
This model is programmed into an easy to use Excel sheet based design approach. In this new design method a comparison is made between the thin ECOserve type pavement and a conventionally designed pavement structure. The appraoch is not focussed on structural aspects (thickness, design) only but includes an assessment and comparison of the environmental impact of different pavement solutions. In the same Excel sheet the earlier mentioned environmental indicators (transport distances, CO2-emission and costs) are calculated and compared. Now the model will be validated with laboratory experiments (large scale testing on slabs). Instead of the planned accelerated full-scale testing of an ECOserve type pavement (D15, Cl4), a demonstration section with real traffic has been constructed. As an outcome of this Cluster, some research needs have been identified and additional, several articles have been published. Partners Partners in Cluster 4 of the ECOserve Network are:
Co-ordinator Robbert Naus
© Copyright 2003 by ECOserve |
