What Protection Should Be Strengthened for GRC Exterior Walls in Acid Rain Areas?

In acid rain areas (pH <5.6), GRC exterior walls face the risk of cement-based materials being gradually eroded by acidic substances, mainly manifesting as surface corrosion, reduced strength, and accelerated steel reinforcement corrosion. In response to this environment, Qinglong Group has developed a systematic "four-in-one" enhanced protection scheme of "improving matrix acid resistance, strengthening surface sealing and isolation, optimizing drainage construction, and enhancing routine cleaning." In projects in acid rain-prone cities such as Chongqing and Guiyang, we have ensured the long-term durability of GRC exterior walls through the use of special cement and multi-layer coating protection.

Enhancing the Acid Corrosion Resistance of GRC Matrix Materials

This is the foundation of protection. Qinglong adopts the following material measures: 1) Selecting acid-resistant cement: give priority to sulfate-resistant cement or concrete mixed with large amounts of admixtures such as slag and fly ash; the hydration products of these materials are more stable and offer better acid resistance than ordinary Portland cement. 2) Reducing permeability: through a low water-cement ratio and the addition of silica fume, the matrix is made extremely dense, slowing the rate at which acid penetrates inward. 3) Using alkali-resistant glass fiber: fibers with high zirconium content are more stable in acidic environments than ordinary fibers, improving resistance at the very essence of the material.

Applying High-Performance Dense Surface Protective Coatings

Putting an "acid rain protection coat" on the GRC surface is essential. Qinglong recommends film-forming protective coatings rather than merely penetrating protective agents: 1) Fluorocarbon coatings: the preferred solution. Fluorocarbon resin has extremely strong chemical inertness, being acid-resistant, alkali-resistant, and stain-resistant, and can form a continuous, dense protective film that effectively isolates acid rain from contact with the GRC matrix. 2) Polyurethane coatings: also offer good chemical resistance. 3) Increasing coating thickness: in severely acid rain-affected areas, the number of coating passes can be increased or thick-film coatings used to provide a thicker physical barrier. Coatings require regular inspection and should be recoated before they fail.

Optimizing Structural Design and Strengthening Maintenance

1) Strengthening drainage: design larger drainage slopes to ensure rainwater (especially acid rain) drains away quickly, reducing its residence time on the facade. 2) Joint sealing: use high-quality sealants resistant to acid rain aging and ensure the seals remain intact. 3) Regular cleaning: establish a regular clean water rinsing system to promptly wash away acidic pollutants and reaction products attached to the surface, avoiding continuous erosion. Protection in acid rain areas is a systematic project requiring control across the entire chain from design, material selection, and construction to maintenance, in order to ensure GRC exterior walls remain "forever young."