Prediction of multiple creep and recovery phenomena for bituminous mixtures and mastics by rheological modelling

Abstract

This study introduces a rheological model for bituminous mixtures and mastics that can accurately fit experimental data curves of permanent deformations. This model provides rheological values for the bituminous binder and aggregates. Unlike classical models, this approach reduces the number of rheological constants required, using fractional exponents to describe better the transition between the elastic and viscous state of the material. The new methodology correlates the permanent deformations observed in bituminous mixtures and mastics using uniaxial compression tests and MSCR. This improves the understanding of creep and recovery phenomena, increasing the predictive capability of permanent deformations in both materials. Thus, it is possible to predict deformations and trends in bituminous mixtures based on mastic deformations. This approach could significantly reduce the resources required to design bituminous mixtures, provided that the nature of the aggregates and their relationship with the binder are known. The proposed model identifies different creep ranges in a bituminous mixture, highlighting elastic and plastic (recovery values. The ability of the model to identify the elasticity of the aggregate set is exemplified by a mixture using ophite coarse aggregate, limestone fine aggregate and hydrated lime filler, showing an elasticity of 125.020 kN/mm, 89.90% more elastic than the limestone filler. This finding validates the need for advanced models to simulate the behaviour of bituminous mixtures and to analyse the creep deformation states in detail, explaining how different materials affect plasticisation. In conclusion, this study provides a deep understanding of the viscoelastic behaviour of bituminous mixtures, with important applications in designing and optimising road infrastructures.