Influence of the geometrical and physical properties of filler in the filler-bitumen interaction

The objective of this laboratory study is to investigate the relationship between the geometrical and physical properties of filler and the consistency of filler-bitumen mixtures and the stripping resistance. Five fillers (3 manufactured and 2 natural) were geometrically and physically characterized with various test methods, including SEM imaging. The filler-bitumen interaction was assessed with two consistency-related mastic tests and a water susceptibility test. SEM images show significant differences in size, shape and surface texture between tested fillers, and a strong correlation with the stiffening effect. It is proposed the inclusion of the f/b(max) ratio, obtained from the absorbing capacity test, in the filler specifications to serve as an indicative threshold value of the filler content added. (C) 2014 Elsevier Ltd. All rights reserved.