What Protection Do GRC Exterior Walls in Acid Rain Regions Need? Acid Rain Protection Solutions and Durability Assurance

GRC exterior walls in acid rain regions are subject to long-term erosion by acidic rainwater and are prone to surface powdering, strength loss, color fading and other problems, which seriously affect service life and appearance quality. Targeted protective measures are needed to enhance the material's acid resistance and erosion resistance. Drawing on project experience in acid rain regions across multiple locations, Qinglong analyzes the core protection solutions.

I. Corrosion Mechanisms and Hazards of Acid Rain on GRC Exterior Walls

Acid rain erosion is insidious and cumulative, with significant hazards. Corrosion mechanism: acidic substances in acid rain, such as sulfuric acid and nitric acid, react with the cement hydration products in GRC to form soluble salts, which are washed away by rainwater, resulting in a loose matrix. Surface damage: long-term erosion causes GRC surfaces to powder and sand, with reduced gloss and faded, yellowing color, affecting the building's appearance. Strength degradation: acidic substances penetrate into the interior and corrode the glass fibers, causing the flexural and compressive strength of components to decline; unprotected GRC components over 20 years old may lose more than 30% of their strength. Joint failure: acid rain accelerates the aging and cracking of sealant, causing joint leakage and further aggravating internal erosion. In inspections of projects in acid rain regions of southern China, Qinglong found many components with surface powdering caused by acid rain.

II. Optimizing Acid Rain Resistance at the Production Stage

GRC's acid rain resistance is improved at the source of production. Material formulation optimization: use high-grade low-alkali cement combined with active admixtures such as silica fume and fly ash at a dosage of 8%-10% to increase matrix density and reduce penetration channels for acidic substances; through formulation optimization, Qinglong raised GRC's acid resistance coefficient to above 0.85. Glass fiber selection: use alkali-resistant glass fibers with an acid-resistant coating applied to the surface to enhance resistance to acid erosion, with fiber content controlled at 3%-4% to ensure strength support. Surface densification treatment: use high-pressure vibration molding technology to reduce GRC surface porosity to below 3% and minimize adsorption of acidic substances; before leaving the factory, the surface is polished and pore-sealed to form a dense protective layer.

III. Strengthened Construction and Surface Protection Measures

Provide all-around protection during the construction stage to block acid rain erosion paths. Surface coating protection: apply special acid-rain-resistant coatings, such as fluorocarbon and polyurea coatings, to form an isolation barrier; fluorocarbon coatings have strong acid corrosion resistance and can effectively withstand acid rain erosion, with a coating thickness ≥0.8mm; Qinglong gives priority to fluorocarbon coatings in projects in acid rain regions. Joint sealing reinforcement: use silicone sealant with strong acid resistance, ensure full filling during construction, and cover the surface with acid-resistant protective tape to reduce direct contact with acid rain. Detail protection: add metal trim strips at water-prone areas such as internal and external corners and anchoring points, combined with sealant for dual protection, to prevent rainwater retention and erosion. Drainage system optimization: design reasonable drainage slopes and install water guide channels to accelerate rainwater runoff and reduce the residence time of rainwater on the surface.

IV. Acid Rain Protection Strategies for the Operation and Maintenance Stage

Regular maintenance extends the acid-rain-resistant service life. Routine cleaning: clean GRC surfaces quarterly with neutral detergent to remove acidic dust and pollutants and avoid cumulative erosion; acidic cleaners are prohibited. Regular inspection: inspect surface coating integrity and component strength every 1-2 years; repair coating damage promptly once found, and take reinforcement measures when strength loss exceeds 10%. Coating renewal: fully renovate the surface coating every 5-8 years to rebuild a complete protection system; Qinglong provides dedicated maintenance plans for customers in acid rain regions, and through regular maintenance extends the service life of GRC exterior walls to more than 20 years. Emergency treatment: rinse surfaces promptly after acid rain to reduce acidic residue and lower the risk of erosion.