Geosynthetic reinforcement for reflective cracking reduction in asphalt pavements

Abstract

A survey by the National Confederation of Transportation of Brazil (CNT, 2011) shows that 47.9% of the country’s roads need urgent interventions to recover satisfactory traffic conditions. This paper presents results of an investigation on the use of geosynthetic reinforcement in asphalt pavements with reference to capping of old courses. The use of geosynthetic reinforcement was intended to reduce crack reflection between an old surface course and the new hot mix asphalt (HMA) layer. In order to investigate crack reflection, two prismatic beams of dense HMA were prepared and geogrids or a geocomposite (geogrid with a geotextile coated with bitumen) reinforcement was placed in between them. An initial crack was induced by cutting the lower HMA specimen and a vertical cyclic loading was applied with a steel plate at the center of top layer. The test was interrupted when the vertical displacement at the surface reached 25 mm. The results show that geogrid reinforcement may increase by up to 15 times the number of loading cycles required to reach the pre-established value of vertical displacement (25 mm). In addition, it was noticed that the severity of the cracking mechanism was reduced and that crack reflection to the upper layer was reduced by the reinforcement inclusion.