Effect of geosynthetic reinforcement insertion on mechanical properties of hot and cold asphalt mixtures

Abstract

The main objective of this research is to analyze the effect of the insertion of a geogrid reinforcement in the mechanical behavior of the hot mix asphalt (HMA) and the cold mix asphalt (CMA). For this purpose, an experimental program was developed, in which HMA and CMA were designed by the Marshall mix design method and specimens with and without a geogrid were molded. The mechanical properties were investigated through tensile strength (Brazilian test), resilient modulus and Marshall Stability tests. The insertion of the geogrid into the HMA provide an increase in the responses of reinforced specimens for the three analyzed tests, which is not observed in the CMA. The adhesion between the asphalt mixture and the geogrid is observed only in the hot asphalt mixture. Therefore, its mobilization shows to be dependent on the temperature of the asphalt mixture, which alters the viscosity of the asphalt binder. It is assumed that the geogrid reinforcement is mobilized due to the adhesion between this geosynthetic element and the hot asphalt mixture. Additionally, the trapping of the asphalt mixture in the geogrid mesh openings provides the formation of a structural system with higher interlocking, lower susceptibility to deformations and as a consequence greater mechanical strength and stiffness, in comparison to unreinforced systems.