Potential application of waste bivalve shells as recycled filler in porous asphalt concrete through rheo-mechanical analysis

Bivalve farming annually generates millions of waste seashells as production by-products. Since seashells mainly consisted of calcium carbonate, they could be used in many construction products offering a sustainable alternative to virgin raw materials coming from mining processes. This research explores the possible use of three bio-fillers from mussel, oyster and clam shells as an effective replacement for limestone filler in porous asphalt concrete. The rheological and mechanical properties of bituminous mastics and mixtures were investigated. The rheological characterization of the three bituminous mastics did not highlight any substantial discrepancy between them and the control one. At the same time, no relevant differences were observed in the physical and mechanical properties of asphalt concretes. Based on the presented outcomes, the use of these experimental bio-fillers in open-graded mixtures can be considered as an eco-friendly alternative to reduce waste bivalve shells and their disposal.