Anticorrosion Behavior of the SiO₂/Epoxy Nanocomposite-Concrete Lining System under H₂SO₄ Acid Aqueous Environment

Concrete structures in the sewer are corroded by sulfuric acid solution resulted from the actions of microorganisms in a sewer environment. Many reports pointed out that it can shorten the service life of concrete sewer networks from 10 to 50 years. Isolation of sulfuric acid solution from the surface of the sewerage concrete structures by using a polymer lining is effective corrosion protection. This study presents the preparation of a silica-epoxy nanocomposite material used for this lining purpose. Diffusion behavior, the cohesion of the lining on the concrete surface under the severer conditions, was investigated. Dispersion and distribution of the nanoparticles in the epoxy matrix confirmed by scanning electron microscopy (SEM) and X-ray diffraction analysis contribute to the enhancement of the lining's barrier properties to water and to H₂SO₄ acid solution at different temperatures. An improvement of cohesion between the concrete and the nanocomposite lining was found. The nanocomposite lining remained cohesive on a concrete substrate almost two times longer than the neat lining when they were exposed to the 10.0 wt % H₂SO₄ acid solution at both 40 and 60 °C. The energy-dispersive system combined SEM analysis results of the pulled-off linings confirmed that the corrosion of the concrete interfaces is because of H₂SO₄ acid. It contributes to the adhesion loss of the lining. Thus, loaded nanosilica particles into epoxy enhance barrier properties, bond strength, and longevity of the service life of the sewerage concrete structure.