Providing a theoretical-analytical framework for innovative non-destructive remediation of ancient stone subsurface structures based on the integration of nanofluids and CO₂ injection

mohammad mohammadi¹ Ehsan Mohtarami² Aminollah Kamali³ Yasser Shahbazi⁴ Mohammad Reza Nemati⁵

1) PhD student in Geomechanical Engineering (Mining Engineering - Rock Mechanics) at Arak University of Technology
2) Faculty member of Arak University of Technology
3) Member of the faculty of the Cultural Heritage and Tourism Research Institute
4) Member of the faculty of the Cultural Heritage and Tourism Research Institute
5) Member of the faculty of the Cultural Heritage and Tourism Research Institute

IOI Code : ABFF-ABDHGA
Publication : 9th International Congress of Developing Agriculture, Natural Resources, Environment and Tourism of Iran(9icsda.ir)
Abstract :
    Ancient subsurface stone structures, as a valuable part of humanity’s cultural heritage, are exposed to gradual weathering, propagation of microcracks, reduction of structural integrity, and mechanical deterioration caused by environmental, moisture-related, chemical factors, and long-term stress conditions. Conventional consolidation methods, particularly cementitious or resin grout injection, are often associated with challenges such as chemical incompatibility with the stone substrate, irreversible blockage of natural porosity, alteration of the stone’s moisture behavior, and reduction of the material’s historical authenticity. In this context, the development of a novel chemical approach that enhances the cohesion and strength of stone while remaining compatible with its mineralogical structure is considered a scientific and conservation necessity. This paper introduces an integrated method based on the simultaneous injection of active mineral nanofluids and CO₂ gas as a non-destructive consolidation process. In this method, nanofluids with nanometric dimensions and high penetration capability disperse within the network of micropores and microcracks of the stone and act as active nuclei for mineral processes. Controlled injection of CO₂ in the presence of natural moisture within the rock mass leads to the formation of weak carbonic acid and initiates carbonation reactions in proximity to free calcium ions or calcitic phases of the substrate. The presence of nanoparticles as nucleation centers increases the rate and uniformity of secondary calcium carbonate crystal formation, resulting in the gradual filling of internal micro-voids, improvement of intergranular bonding, and enhancement of structural cohesion. Unlike conventional methods, the proposed approach is based on endogenous and homogeneous reinforcement of the stone structure through activation of mineral processes compatible with its natural composition and prevents the formation of incompatible phases or distinct artificial layers. This characteristic renders the method a sustainable, relatively reversible option aligned with the principles of scientific cultural heritage conservation. The framework presented in this paper provides a theoretical foundation for the development of a new-generation chemical consolidation technology focused on nanoscale synergy and controlled carbonation reactions in historical stone environments. This research is theoretical–analytical in nature.

Keywords : non destructive remediation ancient subsurface rock structures mineral nanofluids co injection carbon dioxide (co₂) in situ carbonation nanoscale nucleation microstructural consolidation rock compatible restoration cultural heritage conservation