Effect of Geosynthetics on Fatigue Life of Asphalt Pavements

Fatigue cracks are amongst the most important factors for destruction of asphalt pavements, caused by excess loads and traffic in roads and airports. Geosynthetics, as strengthening materials, are able to increase fatigue life and prevent early cracks in asphalt pavements, to a large extent. Efficiency of geosynthetics in asphalt pavements depends on many factors including asphalt mix, temperature, location, etc… This paper studies the performance of two types of geosynthetics (Geogrid and Geotextile) on the fatigue life of asphalt blocks with dimensions of 381 x 63 x 50 mm. Samples were provided of non reinforced, reinforced by geotextiles and geogrids, from asphalt slabs for the purpose of testing. Fatigue tests were conducted by four point beam test, and fatigue load by half-sin wave at a frequency of 10 cycle/sec (no rest period) has been used. The end of fatigue life is defined as decrease stiffness to 50% of its primary stiffness. Results indicated that the fatigue life of reinforcement beam with geogrid and geotextile increase 56% and 50% respectively. Furthermore reinforcing layer increases primary stiffness and reduces rate of cracks propagation in reinforcement specimens compared to non- reinforcement specimens.