The use of marine seashells as aggregates in pervious concretes

Waste recovery is now a favourable solution for technical and economic reasons. The purpose of this study is the valuation of marine co-products – seashells, whose goal is to produce an eco-material that responds to the environmental problem. The experimental study focuses on the idea of replacing natural aggregates with recycled shell aggregates and studying their influence on the properties of pervious concrete. For this purpose, six concrete mixtures were prepared, where three of them were based on natural crushed limestone aggregates with 20% of porosity but had different dosages of cement 250, 300, and 350 kg/m3. The other three concretes have identical compositions, except that crushed shell aggregates substitute the natural aggregates. The obtained results are showing that the use of crushed shells considerably influences the properties of the studied concretes. In the fresh state, all concretes present high slump values and low density. Using shell aggregates improves the mechanical resistance, especially the tensile strength, by bending for the hardened state. Despite their shapes, the shell aggregates used in this study do not affect the concrete porosity, and consequently, draining concretes with good permeability have been obtained.