Alkoxysilane-based sols for consolidation of carbonate stones: Proposal of methodology to support the design and development of new consolidants

Abstract The need of a thoughtful methodology to support the design and development of new consolidation products in built heritage is consequence of the demanding requirements that consolidation treatments in built heritage should fulfill; of physical and chemical specificities of porous carbonate stones and of sol–gel processes complexity. Absence of well-defined planning strategies and systematic studies poses serious difficulties in what concerns validation of new sols for consolidation purposes. This work aims at discussing and to propose a methodology to support the design, development, screening and tailoring of alkoxysilane-based sols to consolidate porous carbonate stones. This methodology addresses three important steps and propose criteria to validate or exclude sols, while the knowledge acquired during the process contribute to the improvement of initial sols. The first step concerns selection of most promising sols from a set of theoretically designed “mixtures”; sols with potential to act as consolidants are assessed in the second step and, in the third step, sols for consolidation of porous carbonate stones are finally proposed. The methodology herein presented contributes to a more systematic and critical design and development of alkoxysilane-based products. It reduces the probability of failure and avoids unnecessary and time-consuming testing plans, often based on trial and error approaches.