Influence of filler fractional voids on mastic and mixture performance

This study proposed the fractional voids test for mineral fillers introduced by Rigden in 1947 and currently adopted as the European norm, as part of asphalt mixture design and quality control. Laboratory testing conducted in this study included a large collection of natural and manufactured fillers currently used in various regions of the United States. Results showed that filler fractional voids influenced mastic viscosity and nonrecoverable compliance. These mastic properties were also found to be highly correlated with mixture performance measures. This study used mixture performance limits to derive mastic limits based on mixture-to-mastic correlations. Regression models developed to predict mastic performance as a function of filler fractional voids and asphalt binder properties were proposed as a means for incorporating fractional voids into the mix design procedure as a quality control measure. This paper discusses the tested materials and the analysis approach and summarizes the data justifying the proposed limits.