Study of acid-resistant behavior of hydroxylated hexagonal boron nitride/isobutyltriethoxysilane composite coatings on sulfoaluminate concrete surfaces

Abstract

Concrete, as the most common building material, is susceptible to erosion in acidic environments, leading to issues such as surface cracking and aggregate exposure. This study employs iso-butyltrimethoxysilane (IBTS) as the coating matrix and incorporates h-BN as a filler material to prepare h-BN/IBTS hybrid latex for addressing the problem of acid corrosion in concrete. By characterizing the binding state between h-BN and IBTS, tracking changes in mortar specimen composition during the corrosion process, this study analyzes the acid corrosion protection mechanism provided by h-BN/IBTS hybrid latex on the surface of mortar specimens. The experimental results demonstrate that hydroxylation-modified h-BN can effectively disperse within IBTS, thus alleviating the agglomeration phenomenon caused by silane volatilization. This enhancement improves the film quality of silane and increases coating tightness. The h-BN/IBTS hybrid latex significantly reduces the corrosion rate of cement mortar specimens in a sulfuric acid environment. This reduction is attributed to the introduction of h-BN, which substantially prolongs the erosion pathway for H+ and SO42- in sulfuric acid, reduces the formation of gypsum within the concrete's internal structure, and effectively preserves the microscale pore structure within the concrete.