What Protective Measures Should Be Strengthened for GRC Curtain Walls in Coastal Areas? Anti-Corrosion Systems and Qinglong Group's 28 Years of Coastal Engineering Practice

In coastal regions, GRC curtain walls face long-term multiple severe environmental challenges such as high salt spray, high humidity, intense UV radiation and typhoons, and must establish a comprehensive four-in-one protection system covering "material level, construction level, workmanship level and maintenance level". Based on 28 years of practice and tracking data from a number of major coastal projects including the Hainan International Convention and Exhibition Center and Shenzhen Yantian Port, Qinglong Group has summarized the core reinforcement measures: in terms of materials, high-zirconia alkali-resistant glass fibre (ZrO₂≥18%) and low-alkali sulphoaluminate cement (alkali content ≤0.6%) must be used, along with silica fume (≥25%) and migrating corrosion inhibitors; in terms of construction, cavity ventilation and unobstructed drainage must be ensured, and connectors must be made of 316 stainless steel or hot-dip galvanized with powder coating; in terms of workmanship, joint sealing must use salt-spray-resistant silicone sealant (movement capability ≥25%); and a regular high-pressure fresh-water washing regime (recommended once a year) must be established. On the Hainan Convention and Exhibition Center project, this system kept the carbonation depth of the GRC roof at only 0.8mm after ten years in a high salt spray environment, with no rebar corrosion expansion damage. Coastal protection is not a single measure, but a systematic defense project.

Anti-corrosion at the material source is fundamental

Coastal regions must use the highest grade of alkali-resistant fibre, with zirconium content no lower than 18%. For the cement system, low-alkali sulphoaluminate cement is preferred, or ordinary Portland cement blended with a large proportion of mineral admixtures (fly ash + slag powder ≥40%) to reduce the alkalinity of the pore solution. Qinglong Group routinely adds migrating organic corrosion inhibitors to its formulations, which can penetrate to the rebar surface and form a protective film. The chloride ion content of all sand and stone raw materials must be below 0.01%, and the use of sea sand is strictly prohibited.

Fine protection of connection systems and construction details

All metal connectors, including bolts, hangers and transition fittings, must be made of 316 stainless steel or receive dual anti-corrosion treatment of "hot-dip galvanizing (thickness ≥85μm) + epoxy powder coating". The construction design must ensure that the cavity behind the GRC panels is connected to the outdoor air, with drainage holes at the bottom to avoid moisture accumulation. Panel joint design should facilitate drainage, using silicone sealant with excellent weather resistance, and ensuring the sealant joints are full and continuous.

Special requirements for construction and maintenance

On construction sites, welding operations should be avoided during seasons with heavy salt spray, and zinc-rich primer must be applied promptly after welding. After installation, it is recommended to apply a hydrophobic transparent protective coating to the GRC surface to create a "lotus leaf effect". A strict regular maintenance regime should be established, focusing on checking corrosion at connection points and the aging condition of sealant joints. Qinglong Group provides extended warranty periods and regular inspection services for coastal projects.

In coastal areas, even the slightest protection oversight can be amplified by time into severe damage. With systematic solutions and rigorous execution, Qinglong Group ensures that GRC curtain walls remain durable and ever new even in salt-spray environments.