Abstract:
Bitumen emulsion asphalts, especially those incorporating marginal and secondary aggregates, are energy efficient, environment friendly, and sustainable alternatives to hot-mix asphalts. This study set out to compare engineering properties of a bitumen emulsion asphalt composed entirely of virgin aggregates with another composed of 55% reclaimed asphalt and 45% virgin aggregates. The aggregates were bound with a slow setting cationic bitumen emulsion composed of 65% base bitumen and 35% water. Marshall specimens molded at varying pre-mix water and bitumen emulsion contents were cured in molds for 24 h before being de-molded and cured for a further 72 h at 40 °C. Dry densities, porosities, and indirect tensile strengths for the cured specimens were determined in dry and soaked states. Virgin aggregate mix, at an optimum binder content of 6.1%, had a tensile strength ratio of 1.3 with corresponding air voids and moisture absorption values of 10.1% and 0.92%, respectively. Similarly, reclaimed asphalt mix at an optimum binder content of 6.2% had a tensile strength ratio of 1.03, with corresponding air voids and moisture absorption values of 7.9% and 0.38%, respectively. Compared to virgin mix, reclaimed asphalt mix had lower air voids and lower moisture absorption values with the overall benefit of enhanced resistance to moisture damage.