Four Decades of the Circular Test Track at the Institute of Engineering UNAM Contributing to Pavement Research in Mexico

The circular test track at the Institute of Engineering UNAM was built four decades ago, between 1970 and 1971. Since its construction, this device has been very valuable for the development, research, and validation of flexible pavement design in Mexico. To date, 40 studies have been conducted on the circular track. It is common for each experiment to build three different sections of pavement to maximize the number of variables to be analyzed. With the information obtained from the experimental sections under service, data on the behavior of sections in different locations throughout Mexico, and experimental results from the circular track, a method for the structural design of flexible pavements was developed. This research program was carried out by the Institute of Engineering, UNAM. The latest version of the pavement design method was published in 2014, called the Structural Design of Flexible Pavements (DISPAV-5 3.0), and is currently the most used method in Mexico for the design of such structures. This resource has a mechanistic-empirical background and includes models to predict asphalt fatigue and permanent deformation damage. However, the models are over 15 years old and are unable to incorporate current characteristics of materials and traffic conditions. This paper describes the role and significance of the circular test track in the development of flexible pavement design in Mexico, the characteristics of the variables that influence pavement behavior and future directions proposed to develop a method of pavement design that considers current needs.