Permanent Deformation Behaviour of Low Volume Roads in the Northern Periphery Areas

ABSTRACT: Roadex II has been an EU financed research project concentrating on the maintenance of the low volume road network in the Northern parts of Finland, Sweden, Norway and Scotland. One of the aims in the Roadex II project has been to assess the permanent deformation behaviour of the low volume roads in these Northern periphery areas especially for the purposes of finding efficient and cost-effective means of maintaining the structural condition of the road network with as little disruption as possible to the vital heavy transports of the forest and fishing industries and agriculture. This paper presents a tentative approach for estimating the risk of permanent deformations in a low volume road and the need for weight restrictions especially during the thawing period of seasonal frost. The assessment is based on a monotonic and repeated load triaxial test series performed at the Tampere University of Technology in Finland and at the University of Nottingham in the UK. The results of these tests have been interpreted using a non-linear finite element analysis to compute the likely plastic strain in the pavement and, hence, the risk of rut development, and a simplified approach proposed for routine use