Coating Granite Monuments with Coconut Oil, As A Natural Technique for Preventive Protection of Sunken Granite, Alexandria - Egypt

Abstract

Granite artifacts are among the most important historical monuments. Many artifacts have been discovered submerged, highlighting their incredible durability and aesthetic appeal. However, these artifacts face threats from underwater degradation factors, so effective preservation is crucial to protect these treasures from further damage. This study investigates the potential of coconut oil as a protective coating for granite artifacts submerged in marine environments. Coconut oil's antimicrobial properties make it a promising candidate for counteracting the effects of marine environment. Achieving the study’s objective requires simulating the actual conditions that submerged granite artifacts face. During the process, a comparison was made to evaluate this innovative natural technique. The compressive strength tests revealed a consistent improvement in peak strength and Young's modulus for coated samples, with increases of 6.21% and 4.3%, respectively. The coated granite samples demonstrated higher compressive strength (102.79 ± 0.59 MPa) compared to uncoated samples (96.78 ± 0.89 MPa), along with more consistent failure planes and enhanced crack resistance. X-ray diffraction analysis highlighted significant mineralogical differences between deteriorated and oil-coated samples. The oil treatment preserved structural integrity, reduced secondary mineral formation, and maintained better crystallinity, indicating effective protection against seawater-induced weathering. Scanning electron microscope observations further confirmed the protective capabilities of coconut oil, showing cohesive particle interactions in coated samples and significant wear and biological growth in uncoated samples. Overall, the results suggest that coconut oil treatment creates an effective barrier against water penetration and ion exchange, preventing weathering processes and offering substantial protection for granite structures in marine environments.