Practical applications

Abstract

The subject of this chapter is the practical application of proposed equations for prediction the viscoelastic properties of bitumen. This Chapter reviews the evolution of penetration and the softening temperature of bitumen during preparation of the asphalt mix at the hot mixing facility and their variation in time during the service life of pavement that causes the variation of viscoelastic properties of asphalt pavement. The requirements of Superpave binder specification to the properties of asphalt are discussed. Those properties can be determined by laboratory testing with the equipment developed by Superpave researchers or they can be estimated for bitumen binders from the relationships described in the monograph. Once the viscoelastic properties of asphalt have been predicted using the methodology described in Chap. 3, there is a need to determine the engineering properties of asphalt concrete as a function of temperature and loading duration for use in evaluating performance and in the mechanistic-empirical thickness design methods. This chapter describes determination of the asphalt concrete relaxation modulus and complex modulus using the mixture rule (Hirsh model). The moduli predictions might be almost as accurate as independent measurements of moduli. For many pavement design and analysis procedures, predicted modulus values of asphalt concrete mixtures can be effectively used.