Water transport properties of cement mortars with mussel shell aggregate

Abstract

Aquaculture and cannery industry are important economic sectors in different countries. It generates big profits and create thousands of employment. However, it also produces lots of waste, being bivalve shells remarkable because of their volume. Shell residue usually is disposed in dump sites producing a great environmental impact. Nevertheless, some research works have proved that it is possible to reuse shells in several industrial activities, including construction.

In general, cementitious pastes are commonly used in construction so that the use of aggregates with less environmental impact can be a way to reduce the carbon footprint associated with construction.

Thus, this study aims to analyse the effect of replacing natural aggregate by heat-treated, crushed and sieved mussel shell in cement mortars for coating. An MC 12.5-X (without air entraining agent) was used for cement mortars, with three substitution percentages of limestone aggregate with mussel shell aggregate: 25%, 50% and 75%. The results were compared with those obtained with a reference mortar without mussel shell aggregate. Different tests of water transfer properties have been studied: capillary uptake, water absorption, water vapour permeability and water permeability. The elongated shape of mussel shell and the presence of organic compounds (polysaccharides), lead mussel shells aggregate to disturb the water transfer properties of cement mortars. Results show that mussel shell mortars hinder water capillary uptake, increase the water absorption and both water and water vapour permeability.