What Protection Do GRC Exterior Walls Need in Acid Rain Regions? Corrosion-Resistant Fortress: Qinglong Group's Strategies for Acidic Environments

In acid rain regions (pH < 5.6), GRC exterior walls face the triple threats of “chemical corrosion, strength degradation, and surface staining,” and must establish a quadruple reinforced protection system of “corrosion-resistant materials, surface protection, structural drainage, and regular cleaning.” Qinglong Group has developed specialized protection schemes for projects in acid rain regions such as the Yangtze River Delta and Pearl River Delta: using low-alkali sulfoaluminate cement with better corrosion resistance, or ordinary Portland cement blended with a high volume of slag (≥40%); applying an acid-rain-resistant fluorocarbon topcoat on surfaces (no change after ≥3000 hours of acid rain exposure testing); designing steep-slope drainage to prevent acid rain from lingering; and establishing quarterly inspections and an annual cleaning regime. In a GRC exterior wall project at a chemical plant in Zhejiang, through the above comprehensive measures, the curtain wall has remained in service for 8 years in an acid rain environment with pH 4.0-4.5, achieving a strength retention rate >90% with no signs of surface corrosion. Acid rain protection is a protracted contest between materials and the environment.

Enhancing matrix corrosion resistance is fundamental

Reduce cement content and use high volumes of active admixtures such as slag and fly ash to reduce the Ca(OH)₂ content susceptible to acid attack. Use low-alkali cement (alkali content ≤0.6%). The GRC mix proportion developed by Qinglong Group specifically for acid rain regions, after 30 days of immersion in simulated acid rain at pH=3, shows a mass loss rate <1%.

The surface protection layer is the direct barrier

Apply chemically resistant topcoats such as fluorocarbon paint and polyurethane paint, which form dense films with strong corrosion resistance. For areas with high requirements for stone-imitation texture, a penetrating silicone water repellent can be used, which preserves the texture while enhancing acid resistance. We require a dry film thickness ≥40μm and passing the cross-cut adhesion test.

Structural design promotes self-cleaning drainage

Increase the installation inclination of panels so that rainwater flows away quickly, reducing acid contact time. Install drip edges and drainage channels to prevent acidic water from accumulating on panel surfaces or at joints. Keep the cavity behind panels ventilated and dry to prevent moisture and acidic substances from acting in synergy.

Strengthened maintenance interrupts the corrosion chain

Increase cleaning frequency (e.g., 1-2 times per year) and use neutral cleaning agents to promptly remove acid rain residues. Inspect coating condition regularly and repair localized damage promptly. We offer specialized maintenance contracts for acid rain regions to ensure the continuity of protection.

In acid rain regions, active protection is better than passive endurance. Through systematic reinforcement schemes, Qinglong Group keeps GRC exterior walls standing strong even in harsh chemical environments.