New Conceptual Model for Filler Stiffening Effect on Asphalt Mastic of Microsurfacing: Fid-Bau Portal

New Conceptual Model for Filler Stiffening Effect on Asphalt Mastic of Microsurfacing

Robati, Masoud

AbstractThis research focused on the stiffening effect of the filler on the asphalt mastic of microsurfacing. One challenge that researchers are faced with in the field of bituminous materials is the interaction between the filler and binder. In this study, a new conceptual model for filler stiffening of the mastic was developed that allows the asphalt mix designer to establish the minimum and maximum filler concentration to incorporate in the asphalt mixture. The proposed model has only one parameter that can be determined using the filler and asphalt emulsion selective properties, such as D10 and pH of the filler and the asphaltene content of the emulsion. A new mechanism for the stiffening effect of filler on mastic was developed based on the physicochemical interaction between filler and bitumen. Based on the model, the increase in mastic stiffness (G*) as a function of the increase in filler concentration can be divided into three regions: diluted region, optimum concentration region, and concentrated region. A new property of filler, named zeta potential, was introduced to determine the stiffening effect of filler on mastic. The effectiveness of the proposed model to capture the true behavior of mastic was also investigated through the correlation between the complex modulus results of mastic and asphalt mix cohesion. Finally, the capability of the model to predict the complex modulus of a new set of filler-binder systems with different properties than those used to develop the model was evaluated. Using the proposed model, there is no need to test the mastic or asphalt mixture at different filler concentrations in order to select the optimum filler amount.