Current Trends in Stone Consolidation Research: An Overview and Discussion

Abstract

This work aims to reveal the recent research trends in the consolidation of stone-built heritage and discuss the advantages and drawbacks of the options and strategies followed by researchers over the last 10 years. Peer-reviewed articles were used to build a database and analyze the details of the stone samples (chemical nature, type of voids, and condition), treatment protocols (application methods and consolidation products), and testing methods to assess the strengthening results of the treatments. In addition, the reported increments in the mechanical properties were also examined to reveal the strengthening capabilities of recent consolidation treatments. The statistical treatment of the results allowed pinpointing the stone varieties that need more frequent consolidation actions (limestone, biocalcarenite, and sandstone) and the aspects that make them more difficult and riskier. Other tendencies were discussed, for example, the predominant use of sound samples over decayed samples (61% vs. 39%) or the predominant use of alkoxysilanes (~46%) over other families of consolidants (e.g., nanolime, ~21%). The current consolidation treatments were found to improve stone strength; however, the most problematic issue in state-of-the-art is the difficulty of identifying high-risk situations of over-consolidation or poor distribution in depth because of either the lack of testing or limitations of the various assessment techniques.

Consolidation of Stone Materials by Organic and Hybrid Polymers: An Overview

“…Among the polymers, lesser importance is paid to acrylic polymers (used for both carbonate‐ and silicate‐based stones), and epoxy resins (for carbonate‐based stones). [ 34 ] Indeed, acrylic and epoxy polymers had been among the most used and studied, especially in the past. However, despite possessing excellent reinforcing properties, which make them particularly useful in the case of erosion and detachment of material, their importance has gradually decreased, especially due to problems related to their incompatibility with some stone substrates ( Figure ).…”

“…As for AS, these react to give rise to the corresponding silicone polymers, which are widely used in the consolidation of stones. In particular, the commercial products Conservare OH [34] Copyright 2023, the Authors. Published by MDPI.…”

“…Data refer to the latest 10 years. Reproduced under terms of the CC-BY license [34]. Copyright 2023, the Authors.…”

Advanced mapping of inorganic treatments on porous carbonate stones by combined synchrotron radiation high lateral μXRPD and μXRF

“…The consolidation of carbonate stones poses a significant challenge in preserving Cultural Heritage (CH) buildings and artifacts due to material decohesion caused by decay 1 . Since the mid-1990s, various inorganic treatments have been developed to restore microstructural cohesion within damaged stones matrixes 2 – 4 .…”