Micromechanics and analogical models for forward and inverse problems in asphalt materials low temperature characterization.

Abstract

The use of increased proportions of Reclaimed Asphalt Pavement (RAP) in the construction of asphalt pavements has become a top priority due to its economical and environmental benefits. However, the blending process that occurs during mixing between the new virgin binder and the RAP aged binder is not well understood, and the question if total blending occurs or other mechanisms takes place that influence the effective properties of the mixture remains unanswered. For many years, various models have been developed and used to predict the composite asphalt mixture properties from the properties of the components.This type of approach is generally known as forward problem. More recently, researchers started to investigate the possibility of predicting binder properties Rom mixture properties (inverse problem). In this dissertation the inverse problem of obtaining asphalt binder properties Rom asphalt mixture properties at low temperature is investigated. First an extensive literature review of the models available is performed. Then the forward problem of predicting the asphalt mixture properties from asphalt binder properties is investigated using one semi-

data obtained with the Bending Beam Rheometer (BBR). Next, the same two models are applied to predict the binder properties from the mixture properties. Then, based on Huet model, expressions that relates the asphalt mixture stiffness to the asphalt binder stiffness and vice versa are obtained.