Roadway Pavement Design Methods, Structural Approaches and Relevant Computer Algorithms: A Critical Review

: Transport and international agencies invest millions of dollars on road projects to support countries develop their infrastructure; therefore, it is important to ensure longer service life and value for money. The primary function of the pavement structure is to keep distresses, including fatigue cracking and permanent deformation, to an acceptable limit so that the pavement can withstand applied vehicle load and repetitions during the service duration. Furthermore, the layered structure of the pavement is intended to ensure that the vehicle contact pressure is distributed in such a way that critical responses at the bottom layer of the pavement are low enough to avoid severe damage. Two typical procedures associated with roadway pavement design are empirical-based and structural analysis methods. However, the empirical-based methods have significant shortcomings, as predicting the mode and extent of pavement performance becomes a major challenge. Alternatively, the structural analysis methods have advanced extensively with computers since they consider crucial factors such as traffic loads, material characteristics and environmental conditions. The imputation of these parameters into the computer algorithm contributes to a better understanding of the mechanical performance of constituent pavement material responses. The predicted responses enable highway engineers to select appropriate pavement compositions that will deteriorate at a satisfactory level during the time of service. The most common structural analysis approaches are analytical modelling and numerical simulation. On the other hand, differences in analysis results generation using these approaches have been a notable concern. This review article presents a synopsis of typical pavement design methods and the problem connected with them; structural approaches to identify factors influencing their accuracy. Furthermore, computer algorithms use due to their usefulness, and the assumptions of layered theories employed in pavement structural design are discussed to uncover potential drawbacks for future upgrades.