A Laboratory Study on the Performance of Geosynthetic Reinforced Asphalt Overlays

Geosynthetics can improve pavement performance in different ways, such as drainage layers, reinforcement and barriers. The use of geosynthetic reinforcement in pavement base and cap layers has increased markedly in the last decades mainly because of better overall performance and greater life of reinforced pavements in comparison with unreinforced ones, as reported in several laboratory and field experiments. This paper presents and discusses results of laboratory load tests on reinforced and unreinforced asphalt concrete layers focusing on the use of geogrids as reinforcement in asphalt overlays. Cyclic loads were applied by a loading platen on asphalt concrete beams consisting of a new cap overlying a cracked cap resting on a compressible layer. Four different types of reinforcements were tested between the new and the damaged asphalt concrete caps under varying values of cyclic loads. The reinforcements tested consisted of a geocomposite, 2 polymeric grids and a wire mesh. The results obtained showed the marked increase in the number of load repetitions due to the use of geogrid reinforcement and that adherence between asphalt concrete and reinforcement is a key issue for a good performance of reinforced overlays.