Creep Behavior of Geocell-Reinforced Recycled Asphalt Pavement Bases

Abstract

The use of recycled asphalt pavement (RAP) materials for roadway construction is a sustainable approach and has received more attention in the recent years. However, permanent deformation, or rutting, is one of the concerns in the use of RAP as a base course due to traffic loading and creep deformation. To minimize the creep deformation, use of a novel polymeric alloy (NPA) geocell was proposed to confine the RAP. One tensile creep test was conducted at a room temperature of approximately 25°C to investigate the creep behavior of the geocell. Nineteen static plate-loading tests were conducted at a room temperature using a medium-sized loading system to evaluate the applied vertical stress-displacement response, the creep strain—time relationship, and the factors influencing the creep deformations of RAP bases. In order to verify the repeatability of the test method, two repeated creep tests were conducted. Well-graded aggregate cover was used in place of the RAP cover to investigate the cover effect on creep deformation behavior of geocell-reinforced RAP bases. The test results showed that the stiffness improvement factors for the geocell-confined RAP over the unreinforced RAP ranged from 1.2 to 1.6. Confinement significantly increased the strength of the RAP. The NPA geocell reduced the initial deformation of RAP samples or bases by 18–73% and their creep rates by 6–60% as compared with the unreinforced base. The creep deformations decreased with an increase in the degree of confinement and a decrease in the applied vertical stress. The well-graded aggregate cover reduced the initial deformation by 58% as compared with the RAP cover. The RAP had a higher creep rate than the geocell in the geocell-reinforced RAP bases.