Utilization of white cement bypass dust as filler in asphalt concrete mixtures

This research was carried out to investigate potential reuses of white cement bypass dust (WCBPD) in the Hashemite Kingdom of Jordan. For this purpose, five different asphalt concrete mixtures were prepared using lime mineral filler (control), 2%, 4%, 6%, and 8% WCBPD substitution for lime mineral filler (LMF). The mixtures were subjected to Marshall testing. Results indicated that the substitution of 2% WCBPD for LMF essentially produced almost the same optimum bitumen content (OBC) as the control mixtures (5.5% by weight of aggregate). The substitution of 4% WCBPD slightly increased the OBC to 5.7% by weight of aggregate without any significant negative effect on asphalt concrete properties (stability, flow, voids in mineral aggregates (VMA), and percent of air voids (Pav)). However, further increase in the substitution ratios (6% and 8%) WCBPD was associated with an increase in the OBC to 6.1% and 6.2%, respectively, which makes them uneconomical mixtures. Thus, 4% WCBPD substitution for LMF would be the optimum used in asphalt paving mixtures.