Sol-Gel Coatings Masonry Sealer for PFAS-Replacement Coatings that Reduces Sorptivity, Acid-Induced Degradation, and Internal Steel Corrosion in Masonry Materials

Abstract

Masonry has been in use for over 6,000 years. This building material is responsible for 70% of all construction, yet masonry degradation exists as a significant operational and occupational issue. Porous features of masonry materials make it especially susceptible to corrosion through water absorption. Currently, preventive methods use sealants and paints as protective coatings to mitigate degradation and corrosion. However, these solutions have demonstrated low durability, remain permeable under environmental stress, limiting their overall effectiveness. Several of these coatings contain per- and polyfluoroalkyl substances (PFAS), which are toxic compounds linked to environmental contamination and human health concerns. PFAS emission is correlated to industrial production and manufacturing processes and transport through several environmental pathways. As a result, sol-gel coatings have emerged as a potential alternative to PFAS-containing 36 coatings as they are highly durable and environmentally protective. However, solgels are notoriously susceptible to high shrinkage, limited coating thickness, and challenges in manufacturing. This study evaluates the effectiveness of a novel Sol-Gel-based Self-Cleaning Hydrophobic Nanocoating (SCHN 158), which can be mass manufactured (in tons), providing economic relief while improving durability and acid resistance in all masonry materials. SCHN 158 was compared with uncoated masonry samples and commercial coatings. Mass change analysis, acid corrosion testing, and sorptivity measurements were used to test coating performance. SCHN 158 demonstrated minimal mass loss, maintained structural integrity under acid exposure, and significantly reduced water absorption compared to untreated and commercial coating samples. These findings demonstrate potential applications in manufacturing, construction, and resource extraction fields by SCHN 158’s established effectiveness in limiting water and acid penetration. This highlights its potential to enhance masonry, infrastructure durability, and metal reinforcement protection in harsh conditions such as found for reinforced rebar, pipes in fracking and irrigation pipes.