In this review, we present a survey on hydrophobic surface treatments of concrete, important protection tools against deterioration and corrosion phenomena. In the frame of a standardized distinction in coatings, pore blockage, and impregnation methods, we highlight the huge variety of compounds and formulations utilized, and the different performances reached in terms of water contact angle, water absorption, chloride penetration, and, rarely reported, anti-icing/icephobic action. Our view covers the spectrum of the surface treatments, but also makes a comparison with hydrophobic bulk modifications of concrete, procedures often utilized as well; further, novel proposals of more sustainable routes are presented. We note that coating and impregnation, preferably when based on polyurethane and silane/siloxane, respectively, appear more effective against water ingress. The achieved wetting character is hydrophobic or, at most, overhydrophobic. Superhydrophobic coatings for concrete have been obtained by embedding nano-powders in hydrophobic emulsions, allowing to add a nanotexture to the preexisting complex roughness of the material. Concrete treated with this type of coating has also recently shown a pronounced icephobic character, a parameter that goes beyond the freeze–thaw characterization usually conducted on cement-based materials.
25 November 2023 in Science of The Total Environment
The topic of sustainability of reinforced concrete structures is strictly related with their durability in aggressive environments. In particular, at equal environmental impact, the higher the durability of construction materials, the higher the sustainability. The present review deals with the possible strategies aimed at producing sustainable and durable reinforced concrete structures in different environments. It focuses on the design methodologies as well as the use of unconventional corrosion-resistant reinforcements, alternative binders to Portland cement, and innovative or traditional solutions for reinforced concrete protection and prevention against rebars corrosion such as corrosion inhibitors, coatings, self-healing techniques, and waterproofing aggregates. Analysis of the scientific literature highlights that there is no preferential way for the production of “green” concrete but that the sustainability of the building materials can only be achieved by implementing simultaneous multiple strategies aimed at reducing environmental impact and improving both durability and performances.
Spills, leaks, and other environmental aspects associated with petroleum products cause hazards to human health and ecosystems. Chemicals involved are total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAHs), solvents, pesticides, and other heavy metals. Soil vapor extraction (SVE) is one of the main in-situ technologies currently employed for the remediation of groundwater and vadose zone contaminated with volatile organic compounds (VOCs). The performance of an SVE remediation system was examined for a petroleum hydrocarbon-contaminated site with attention to remediation targets and final performance. The study assessed: (1) the efficiency of a full-scale remediation system and (2) the influence of parameters affecting the treatment system effectiveness. Results showed how VOC concentration in soil was highly reduced after four year treatment with a global effectiveness of 73%. Some soil samples did not reach the environmental threshold limits and, therefore, an extension of the remediation period was required. The soil texture, humidity, permeability, and the category of considered pollutants were found to influence the amount of total extracted VOCs.
1 February 2022 in Science of The Total Environment