Bivalve Shells as a Building Material. A Real Case Application

Abstract

In a research project, Biovalvo Project, developed in the University of A Coruña, mussel shells by-products of the local canning industry were converted into a building material. The main milestone of the project was the construction of an experimental building as a real case application. This building used heat-treated and grinded mussel shells in all the building solutions: as aggregates in the foun-dation concretes and in the coating mortars as partial substitution for conventional aggregates. They were also used as the only thermal and acoustic insulation for the entire envelope. Derived from the project, a PhD thesis was developed where a deep analysis of the mussel shell materials was carried out. Properties of cement-based concrete were assessed including workability, mechanical strength, permeability, absorption, weight loss and microstructure. In the case of plasters and renders, mussel shells mortars were made with two binders: cement and air lime. The study included the analysis of mortars’ properties such as consistency, stiffening time, mechanical behaviour, air content, porosity, pore size distribution, microstructure, carbonation and hygric behaviour. Thermal and acoustic behaviour of mussel shells as loose fill insulation were assessed, and also their compaction and settling capacity were anal-ysed. The potential environmental impact of the mussel shell product was performed using a cradle-to-gate approach. In the case of building solutions, the U-value calcu-lation of the opaque elements, based on laboratory test, allowed to design an experi-mental building with a low energy consumption. This manuscript highlights the high potential that offers this by-product and summarizes the main results of the Biovalvo Project.