Geosynthetics have been used for reinforcement in roads in the Nordic countries for more than 50 years. Roads in these countries have relatively low traffic volume and the main deterioration mechanisms are related to soft subsoil, high water content and frost actions. The geosynthetics are used to improve bearing capacity and reduce deformations. The solutions are based on an evaluation of deterioration mechanisms and the design is to a large extent based on experiences from the field. Geosynthetics are commonly used in the sub-base or base layer to improve the resistance to deformation in rehabilitation and upgrading of existing roads. However, despite positive effects are verified through experiences, no technically sound design model is existing. To a large extent design is based on producer specific empirically based design recommendations. This means that comparison between different solutions with reinforced base layers and comparison with more conventional solutions are very difficult. This is a major obstacle to the implementation of geosynthetic reinforcement into conventional road design procedures and means that the use of reinforcement in the base layer only to a limited extent has been taken into account in general recommendations for road design. The paper presents some results from research projects and experiences from the field. It also presents a basis for developing a design model for reinforcement in granular materials and recommendations related to the use of geosynthetic reinforcement in granular materials in road pavements.
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