Evaluation of permanent deformation of geogrid reinforced asphalt concrete using dynamic creep test

Permanent deformation (rutting) is one of the distresses that can adversely affect the bituminous surface of pavement structures, particularly in hot climates. The geosynthetics reinforcement of hot mix asphalt is one of the means to combat rutting. In this study, a dynamic creep test was performed on asphalt concrete samples reinforced with four different types of fiberglass grid as well as on unreinforced samples. The fiberglass grids used in this study contained two different sizes of grid openings and two tensile strengths, allowing us to test for the mesh size and tensile strength effects of the grids on the permanent deformation behavior of double layered asphalt concrete. In addition, we tested a recently developed creep curve model has been verified and used this to study the creep behavior of the samples in the primary and secondary regions of the creep curve, as well as determining the boundary point of the regions. The results suggest that not only grid tensile strength, but also grid mesh size is of great importance in combatting permanent deformation of fiberglass grid reinforced asphalt concrete within the conditions and grids used in this study. In a nutshell, higher tensile strength and/or smaller mesh size grids lead to overall better performance of grid reinforced samples. Moreover, great care must be taken when the creep curves are not reached in the tertiary region, and the creep rate must be taken into account to avoid any misinterpretation of the results.