What protective measures should be strengthened for GRC curtain walls in coastal areas?

GRC curtain walls in coastal areas face multiple challenges such as high salt fog, high humidity, and strong typhoons, and their protection measures need to be systematically strengthened across four dimensions: material formulation, structural design, surface treatment, and regular maintenance. Based on successful experience from typical coastal projects such as the Hainan International Convention and Exhibition Center and Sanya Festival Plaza, Qinglong Group has developed a targeted protection technology system. In the 120,000-square-meter roofing project of the Hainan International Convention and Exhibition Center, we adopted comprehensive measures including sulfate-resistant sulfoaluminate cement-based GRC, silane-impregnated surface protection, and 316 stainless steel connection systems, keeping the curtain wall intact for ten years in a highly corrosive environment.

Optimizing the material formulation is the foundation of protection. Coastal GRC should use sulfate-resistant cement or sulfoaluminate cement to significantly improve resistance to chloride ion penetration. Qinglong's coastal-specific formulation controls the water-binder ratio below 0.32 and incorporates active admixtures such as silica fume and mineral powder, reducing the 28-day chloride ion diffusion coefficient of the material to below 2.0×10⁻¹²m²/s. At the same time, magnesium oxide content is strictly controlled to prevent later-stage expansion and cracking. In the Yangjiang Victoria Manor project, this optimized formulation enabled GRC components to maintain good durability in an environment only 500 meters from the coastline.

Sound structural design directly affects protection effectiveness. In coastal projects, Qinglong adopts a "large pitched roof, small overhanging eave" drainage design to prevent rainwater retention. Panel joint widths are appropriately increased to 15-20mm, and a deep sealant application technique is used to ensure the sealant remains effective after thermal deformation. All penetration holes are provided with drainage slopes to prevent water accumulation. In the connection system design, hangers with drip edges are used to block capillary water rise paths. These detail-oriented construction measures reduce the accumulation of moisture and salt at the source.

Surface protection is the key barrier against salt fog corrosion. Qinglong recommends using silane or siloxane impregnating agents for surface treatment, which penetrate to a depth of 3-5mm and form a hydrophobic layer within the capillary pores without affecting the material's breathability. For critical projects, a fluorocarbon coating can be applied to seal the surface and further improve corrosion resistance. In the Xiamen International Conference Center project, optimizing the surface protection system extended the expected service life of the GRC curtain wall in the maritime climate by more than 50%.

Regular maintenance is the guarantee of long-term protection effectiveness. Qinglong recommends a comprehensive annual inspection of coastal GRC curtain walls, focusing on sealant aging, the condition of the surface protection layer, and corrosion of connection components. Maintenance records should be established to document each inspection and repair, providing a basis for preventive maintenance. Through refined protection over the full life cycle, coastal GRC curtain walls can fully meet the 50-year design service requirement.