Evaluating the Protective Effects of Calcium Carbonate Coating on Sandstone Cultural Heritage

Abstract

The purpose of this work was to use different surfactants to deposit different crystalline calcium carbonate films on the surface of sandstone through a simple double displacement reaction. This was done to test the protective effects of calcium carbonate coatings based on water absorption, moisture permeability and weather resistance. Experimental results showed that the air permeability of the stone treated with vaterite calcium carbonate was reduced, but that this did not affect water vapor’s access into and out of the stone. Compared with untreated stone, the water absorption rate was reduced 0.5 times, and the weather resistance increased by 4 times due to small crystal grains, high solubility, and deep penetration hindering the erosion of water and soluble salts. These findings are expected to provide useful suggestions for the protection of stone cultural heritage.

Application of SiON Coatings in Sandstone Artifacts Conservation

“…The stone used in the test was fine−grained clastic feldspathic sandstone. Previous research revealed that the porosity of untreated sandstone tested with the mercury intrusion method was 12.48 percent, with an average pore diameter of 1272.68 nm [36].…”

SiO2 Nanoparticles as New Repairing Treatments toward the Pietraforte Sandstone in Florence Renaissance Buildings

“…For comparative study in terms of consolidation efficiency, CaCO 3 and the commercial Estel 1000 consolidating reagent have been selected. This choice lies in the fact that CaCO 3 is part of the Pietraforte matrix and also its main cement element, while the Estel 1000 represents a consolidating agent, widely applied on Florentine Pietraforte sandstones [16]. The latter consists of ethyl silicate in white spirit D40 solution.…”

“…For this reason, conservation scientists have thought and designed new materials based on silicates, but with different properties that derive directly from the dimensions confined in the nanoscale, as the different dispersibility in several different working mediums, generating a nanosuspension and not a consolidating agent in a solvent. According to what has been said previously, several nanoparticles have been synthesized and applied to Florentine sandstones by many authors in literature, such as SiO 2 [8][9][10][11], Ca(OH) 2 /nano lime [12][13][14], CaCO 3 [15,16], nanocomposite materials [17,18] and hybrid nanocomposite materials based on consolidating agents and biocide, as reported in the literature [19].…”

Insight into a Bentonite-Based Hydrogel for the Conservation of Sandstone-Based Cultural Heritage: In Situ Formation, Reinforcement Mechanism, and High-Durability Evaluation

“…As is well known, deterioration and losing of the cementing materials inside the sandstones is the main factor underlying sandstone degradation. − Multiple protective strategies have been employed to mitigate this factor. One approach uses synthetic polymers, including PVA, polyacrylate polymers, fluoropolymers, and polyalkylsiloxane coatings. − Another uses inorganic or hybrid materials, such as those based on SiO 2 or CaCO 3 . ,,− Unfortunately, these reported protective materials still have some problems. For example, they may be unable to permeate inside the sandstones, simply coating the surfaces. ,,, The result is poor protection, poor compatibility with the sandstone matrix, or secondary damage (significant differences in air permeability, color differences). − In addition, the use of organic solvents could cause serious environmental pollution. ,, It is urgent that more effective and environmentally friendly protections be developed.…”

“…For example, they may be unable to permeate inside the sandstones, simply coating the surfaces. 14,19,22,23 The result is poor protection, poor compatibility with the sandstone matrix, or secondary damage (significant differences in air permeability, color differences). 21−24 In addition, the use of organic solvents could cause serious environmental pollution.…”