Search Results (2)

This study examines the rapid degradation of oak mooring piles caused by shipworms in Venice, Italy. In the last few decades, this problem has raised significant safety and environmental concerns, as the piles often need to be replaced every 18–24 months. The sound basic density and diameter of 22 oak piles were analysed after being exposed to shipworm attacks for 18–240 months to determine whether denser piles or larger diameters influence the rate of decay. This was performed to assess whether larger cross sections or higher densities of the piles could imply an increased durability against marine borers. The impact of environmental factors such as temperature, salinity, pH, and dissolved oxygen levels was also assessed. The results highlighted that pile density and diameter do not significantly influence the resistance against shipworms, while rising temperatures (+2 °C in the past two decades) may contribute to accelerating shipworm activity. These phenomena are worsened by the arrival of warm-water shipworms since 2013, exhibiting greater aggressiveness in wood degradation. Furthermore, the potential impact of storm surge barriers on shipworm activity remains an open research topic. Alternative materials and protection techniques introduced since 2015, such as polyurethane piles or metal stapling, face environmental and logistical challenges. Despite these alternatives, many new oak mooring piles are still installed in Venice without protection and are vulnerable to rapid deterioration. Addressing these issues requires multidisciplinary research to develop sustainable materials and preservation techniques for maintaining infrastructure in Venice. Full article

In this work, new treatments based on multi-walled carbon nanotubes (MWCNTs), MWCNTs decorated with zinc oxide (ZnO), MWCNTs decorated with hydroxyapatite (HAp) and MWCNTs decorated with silver (Ag) nanoparticles dispersed in PHBHV solution are proposed for improving sound oak wood properties. We hypothesize that the solutions containing decorated MWCNTs will be more efficient as wood consolidants, not only because of the improved mechanical properties of the treated wood but also because of the hydrophobic layer created on the wood surface. In order to test these hypotheses, the treatments’ potential was investigated by a number of complex methods, such as colorimetric parameter measurements, water absorption tests, mechanical tests, artificial aging and antifungal tests. The data confirm that the treated wood materials have moderate stability, and the color differences are not perceived with the naked eye. A significant improvement of the treated samples was observed by water absorption, humidity and mechanical tests compared to untreated wood. The best results were obtained for samples treated by brushing with solutions based on decorated CNTs, which confirms that a uniform and thicker layer is needed on the surface to ensure better protection. The wood behavior with accelerated aging revealed that the control sample degraded faster compared to the other treated samples. Antifungal tests showed that higher growth inhibition was obtained for samples treated with 0.2% MWCNTs_ZnO + PHBHV. Considering all of the obtained results, it can be concluded that the most effective treatment was MWCNTs_ZnO + PHBHV at a nanocomposite concentration of 0.2%, applied by brushing. Thus, wood protection against mold and fungi will be achieved, simultaneously ensuring improved mechanical strength and water barrier properties and therefore maintaining the structural integrity of sound oak wood over time. Full article