Valorisation of Tuff and Brick Wastes by Alkali Activation for Historical Building Remediation

Nowadays, the preservation and restoration of a historical building needs to be faced in accordance with a novel sensibility regarding the environment in order to preserve the building for future generations. In this context, the scientific community is focusing on novel and sustainable materials and techniques that allow for durability and mechanical performance as well as compatibility with the existing heritage. Alkali-activated materials represent a great challenge to the production of new materials, starting from the existing ones, with the goal of reducing consumption, emission of greenhouse gases and environmental impact. This study deals with the valorisation of waste materials coming from demolition and construction activities in the manufacture of geocomposites suitable for the restoration and conservation of historical heritage. In particular, waste from tuff sawing and brick grinding were used as raw materials, and then the geopolymeric samples produced were characterized based on a physical-chemical and mechanical point of view in order to investigate their performance and evaluate their suitability as materials for a historical building's recovery. The results showed that brick waste-based geocomposites were more compact than the tuff-based ones, as shown by the higher-density values and the lower values of open porosity and water absorption and as further confirmed by the trend of the mechanical performance. Moreover, experimental data showed that the physical and mechanical properties of both bricks and tuff waste-based geocomposites, even with different waste content, are compatible with existing building materials as well as traditional repairing products.