Typical drainage problems in Northern Europe and the effect of improving drainage

Resumé

Typical drainage problems in the Northern Periphery area of Europe have been addressed in this paper. Field observations for roads on sloping ground shows large differences in rut depth and roughness on the road cut side compared to the embankment side. The road cut lane has the ground water table much closer to the road surface and therefore also a higher moisture content in the road structure materials and the subsoil. For 20 % of the analysed roads the rut depth on the road cut lane is 1.5 times larger than on the other lane. Just 12 % of the roads have larger rut depth on the embankment lane. Predictions models are used to demonstrate the change in lifetime (calculated as number of standard axles) as a function of moisture content. Both field observations and prediction models show that improving the drainage will give a large profit in lifetime and also the life cycle costs. These are calculated for a period of 50 years and the conclusion is that maintaining and improving the drainage system is cost effective and must be prioritised
among other maintenance activities. The first step in strengthening a road should be to make sure that the drainage system work properly and should be improved 1-2 years before paving.