This thesis studies the mechanics which can be associated with asphalt concrete compaction and develops continuum models in a general thermo-mechanical setting which can be used in future work to corroborate experimental compaction experiment results. Modeling asphalt concrete compaction, and also the ability to thereby predict response of mixes, is of great importance to the pavement industry. Asphalt concrete exhibits nonlinear response even at small strains and the response of asphalt concrete to different types of loading is quite different. The properties of asphalt concrete are highly influenced by the type and amount of the aggregates and the asphalt used. The internal structure of asphalt concrete continues to evolve during the loading process. This is due to the influence of different kinds of activities at the micro-structure level and to the interactions with the environment. The properties of asphalt concrete depend on its internal structure. Hence, we need to take into account the evolution of the internal structure in modeling the response of asphalt concrete. A theoretical model has been developed using the notion of multiple natural configurations to study a variety of non-linear dissipative responses of real materials. By specifying the forms for the stored energy and the rate of dissipation function of the material, a specific model was developed using this framework to model asphalt compaction. A compressible model is developed by choosing appropriate forms of stored energy and rate of dissipation function. Finally, a parametric study of the model is presented for a simple compression deformation. It is anticipated that the present work will aid in the development of better constitutive equations which in turn will accurately model asphalt compaction both in laboratory and in field. Distinct numerical approaches have been used to demonstrate the applicability of the theoretical framework to model material response of asphalt.
This thesis studies the mechanics which can be associated with asphalt concrete compaction and develops continuum models in a general thermo-mechanical setting which can be used in future work to corroborate experimental compaction experiment results. Modeling asphalt concrete compaction, and also the ability to thereby predict response of mixes, is of great importance to the pavement industry. Asphalt concrete exhibits nonlinear response even at small strains and the response of asphalt concrete to different types of loading is quite different. The properties of asphalt concrete are highly influenced by the type and amount of the aggregates and the asphalt used. The internal structure of asphalt concrete continues to evolve during the loading process. This is due to the influence of different kinds of activities at the micro-structure level and to the interactions with the environment. The properties of asphalt concrete depend on its internal structure. Hence, we need to take into account the evolution of the internal structure in modeling the response of asphalt concrete. A theoretical model has been developed using the notion of multiple natural configurations to study a variety of non-linear dissipative responses of real materials. By specifying the forms for the stored energy and the rate of dissipation function of the material, a specific model was developed using this framework to model asphalt compaction. A compressible model is developed by choosing appropriate forms of stored energy and rate of dissipation function. Finally, a parametric study of the model is presented for a simple compression deformation. It is anticipated that the present work will aid in the development of better constitutive equations which in turn will accurately model asphalt compaction both in laboratory and in field. Distinct numerical approaches have been used to demonstrate the applicability of the theoretical framework to model material response of asphalt.