A Reversibly Removable VAE-Cement Repair Material for Stone Carving Relics Conservation

In stone heritage conservation, conventional inorganic materials frequently suffer from inadequate impermeability and suboptimal adhesion, whereas organic systems commonly exhibit insufficient long-term durability. This investigation develops a removable cement composite modified with vinyl acetate-ethylene copolymer (VAE) to overcome these constraints. Through the incorporation of 3% VAE emulsion combined with 1% nano-SiO2 and 1.5% nano-CaCO3, a continuous polymer network forms within the matrix, optimizing the pore structure and reducing the porosity to 19.7%, thereby substantially enhancing the impermeability. The formulated composite demonstrates a compressive strength of 55.47 MPa alongside a sustained improvement in flexural strength reaching 10.78 MPa, indicating effective material toughening via interfacial reinforcement and crack-bridging mechanisms, as validated by molecular dynamics simulations. A strategically designed soluble VAE interlayer endows nondestructive removal of the repair material. Comprehensive durability evaluations under acidic, alkaline, saline, and wet–dry cyclic conditions reveal significantly superior performance retention relative to conventional cement paste, attributable to the protective barrier function of the polymer network. Twelve-month outdoor exposure testing further corroborates its enduring stability under practical environmental conditions. This research establishes a high-performance, minimally invasive, and sustainable methodology for the restoration of stone cultural heritage artifacts.