Laboratory Evaluation of the Use of Florida Washed Shell in Open-Graded Asphalt Mixtures

Abstract

This study investigates the substitution of conventional aggregate with a Florida washed shell in open-graded asphalt mixtures and evaluates the optimal substitution percentage in aggregate gradations of various nominal maximum aggregate sizes (NMASs) (i.e., 4.75, 9.5, and 12.5 mm). Laboratory experiments were performed on open-graded asphalt mixture specimens with the coarse aggregate of sizes between 2.36 and 12.5 mm being replaced by the Florida washed shell at various percentages (0, 15, 30, 45, and 100%). Specimen properties relevant to the performance of open-graded asphalt mixtures in the field were tested, evaluated, and compared. Specifically, a Marshall stability test, Cantabro test, indirect tensile strength test, air void content test, and permeability test were conducted to evaluate the strength, resistance to raveling, cracking resistance, void content, and permeability of open-graded asphalt mixtures. The results show that there is no significant difference in the Marshall stability and indirect tensile strength when the coarse aggregates are replaced with Florida washed shell. This study also found that the optimum percentages of Florida washed shell in open-graded asphalt mixture were 15, 30, and 45% for 12.5, 9.5, and 4.75 mm NMAS gradations, respectively.

Performance of Porous Asphalt Mixtures Containing Recycled Concrete Aggregate and Fly Ash

“…The Marshall stability and flow test was carried out in accordance with AASHTO T 245 specifications [36]. To avoid the significant creep deformation in the PAM specimens during the high temperature conditioning procedure, this test was conducted at 25 • C instead of 60 • C [5,37]. The cylindrical specimen was loaded inside a Marshall breaking head in the diametrical direction to determine the maximum load supported.…”

“…Recent years have seen a significant increase in the popularity of alternative pavement designs, which are intended to help to mitigate the environmental consequences of civilization's expansion [5]. For its excellent stormwater runoff reduction function, porous asphalt mixture (PAM) pavements are becoming increasingly widespread in the paving industry [6].…”