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(1) Background: In time, stone monuments suffer a process of aging and loss of aesthetic and mechanical properties. In order to restore and stop the loss of their properties, various treatments are used, and in this context, a new class of discovered materials with interesting properties are layered double hydroxides, or LDHs. (2) Methods: The LDHs, prepared by a coprecipitation method, were characterized by the structure by X-ray diffraction, composition by FT-IR spectroscopy and X-ray fluorescence spectroscopy, size by diffuse light scattering, and porosity by N2 adsorption/desorption. Additionally, some microscopy techniques such as optical microscopy and SEM/EDAX were used for surface aspects and morphology, and finally, all these were checked with ImageJ software for representative roughness parameters of the treated surfaces by brushing or incorporation. (3) Results: The prepared materials show different degrees of crystallinity and textural properties, and the dispersion of the material presents good stability in time in water/ethanol mixtures. Treatment with the LDH dispersion applied by brushing led to improvements in the mechanical properties (about a 5% increase in compressive strength), to an increased surface stability (about 30%), and to an improvement in the resistance to freeze–thaw cycles. The textural properties of the specimens’ materials were not altered by these treatments. (4) Conclusions: The order of the consolidation efficacity was CaMgAl-LDH > MgAl-LDH > CaAl-LDH, better for application by brushing than by incorporation.

The aim of the paper consists in the study of three Romanian types of marble (Ruschita, Albesti, Carrara) with different compositions in different temperature conditions, for different periods of time. The three samples were exposed to two different types of treatments: 25 cycles of freeze-thaw (according to SR EN 12371) and 3 cycles of exposure to high temperatures (400 °C for 1 hour). Following the freeze-thaw cycles, small differences in chromatic parameters could be observed (∆E = 2.2 for Carrara Italia marble and ∆E = 7.2 for Rușchița pink marble). The freezing coefficient for all samples is low (0.016% - 0.029%). Following exposure to high temperature treatment, the samples show large differences in chromatic parameters (∆E = 43.47 for Albesti marble) and significant changes in gloss. The surface of the samples showed cracks and microcracks. Based on the results of this study, the following conclusions can be drawn: Thermal cycles can cause the mechanical disintegration of the outer part of the marble, starting from the discontinuities contained in the rock and between the faces between the different minerals that form the stone. Exposure to high temperatures will result in a loss of adhesion between the surface grains on the sample surface. The degradation processes have been investigated.

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