Fly Ash as a Mineral Filler and Anti-Strip Agent for Asphalt Concrete

摘要

This project studied the effectiveness of fly ash and other filler-additives as replacements for portland cement and hydrated lime in production of asphalt concrete mixtures. Both mixture design and moisture resistance characteristics were studied. Properties of asphalt concrete containing additions of two different fly ashes at 1, 3, and 6 percent; four combinations of cement, lime, and fly ash; lime kiln dust at 2 percent; and residue from a pilot copper extraction process at two levels, were compared to those of mixtures containing only natural fines; a chemical anti-strip; 2 percent hydrated lime; and 2 percent portland cement. Results of the mixture design phase indicate that with respect to Marshall mixture design criteria, acceptable asphalt concrete mixtures can be produced in the laboratory with up to 6 percent fly ash by weight of aggregate. Differences noted with mixtures containing up to 6 percent fly ash were (1) reduced asphalt requirements and (2) lowered V.M.A. values.