Computational Methods for Road way Analysis and Design

In this chapter, a brief overview is given of the computational methods required to perform finite element analyses of asphalt concrete and asphaltic road ways. It is shown that the finite element method may be deployed to predict both temperature and moisture within the road way as functions of time and spatial coordinates, and these may then be utilized, together with input loads on the road way, and to predict mechanical response, including stresses, strain, and displacements of the pavement. Newton iteration is discussed as a means of accounting for nonlinearities due to plasticity, viscoelasticity, viscoplasticity, and evolving cracks within the pavement. The finite element method is then utilized to demonstrate the power of computational mechanics in predicting the performance of road ways as a functions of global, local, and even microscale input variables, including tire pressure distribution, fillers, fines, aggregate, base material and compaction, and even environmental effects. As tools for computational analysis both micromechanics and multi-scaling are discussed in some detail, with emphasis placed on how designers can account for the effects of controllable parameters such as mix volume fractions and pavement thickness to improve road way performance, attention is paid to how these parameters can affect pavement rutting and cracking. Tools discussed in this chapter will therefore serve the designer well in improving performance of road ways of the future.