Waste Industrial materials and geopolymers: new sustainable perspectives assessable in Conservation of Cultural Heritage

The sustainable conservation of built Cultural Heritage (CH) has become crucial because of the faster evolution of the degradation phenomena and the growing attention to environmental safeguard. Thus, different materials are combined and tested for applications in CH; geopolymers are included in this new frontier as a possible component in consolidants or concretes. They show features in compliance with the prerequisites requested for modern materials such as a lower carbon footprint than traditional concrete, the versatility and sustainability suggested by the possibility to be mixed with industrial waste in the preparation of restoration mortars and the reduction of water amount in the synthesis of the products. In this work, Na-polysialate(siloxo) geopolymer concretes were formulated according to the method [1] mixing different amounts of metakaolin as precursor, a waste industrial silt as additive and an alkali activating solution of NaOH and sodium disilicate. Uniaxial compressional test, XRD analysis, and SEM-EDS determined the mechanical properties and the evolution of the polymerization in the concretes. Data indicate that the combinations tested provided different geopolymer concretes, where the water amount has a key role in the strength reached. The results encourage the research on geopolymers in issues related to the restoration and conservation of CH.