Introduction: The term marble derives from ancient Greek and has the meaning of “shining stone”

This study investigates the potential of Layered Double Hydroxides (LDH) as additives to improve the durability and physical properties of cement-based mortars, with a focus on freeze-thaw resistance. Three LDH types—MgAl-LDH, CaAl-LDH, and ZnAl-LDH—were synthesized and incorporated into mortar at a 1/1000 w/w ratio. X-ray diffraction (XRD) and wavelength dispersive X-ray fluorescence spectroscopy (WDXRF) were used to characterize the LDHs, and the effects of the additives on mortar density, water absorption, and durability under 30 freeze-thaw cycles were examined. Results revealed that MgAl-LDH provided the best freeze-thaw resistance, likely due to its smaller crystallite size and enhanced cement hydration. CaAl-LDH offered moderate improvements, while ZnAl-LDH negatively impacted the mortar’s mechanical integrity, leading to higher degradation. The study demonstrates the potential of LDH additives—particularly MgAl-LDH—in improving the durability of cementitious materials, although further optimization is required to enhance long-term performance and resistance to environmental stresses.

The preservation of stone and mortar elements in cultural heritage structures is increasingly challenged by environmental degradation, pollution, and biological fouling. Photocatalytic coatings represent a promising approach for developing self-cleaning and pollutant-degrading surfaces. In this study, a silver-modified ZnAl-layered double hydroxide (Ag@ZnAl-LDH) was synthesized via coprecipitation and applied as a coating on mortar substrates. The structural and compositional characteristics of the prepared materials were investigated using X-ray diffraction (XRD) and wavelength-dispersive X-ray fluorescence (WDXRF). The XRD pattern confirmed the formation of a ZnAl-LDH phase (JCPDS 48-1022) with carbonate as the main interlayer anion, along with additional reflections attributed to ZnO (JCPDS 99-0111) and silver-containing species. The photocatalytic activity was evaluated through the degradation of methylene blue under natural illumination (700 W/m²), monitored via CIELAB colorimetric parameters. The results demonstrated that Ag@ZnAl-LDH coatings promote the photodegradation of organic dyes, indicating potential for developing functional, self-cleaning coatings for the protection of heritage materials.