What Risks Can Excessive Chloride Ion Content in GRC Materials Cause? How to Control It? Chloride Erosion Protection and Qinglong Group's Control System

Excessive chloride ion content in GRC materials can trigger multiple risks such as steel reinforcement corrosion, fiber degradation, and matrix expansion, severely threatening structural safety and durability. Based on 28 years of engineering practice, Qinglong Group controls the chloride ion diffusion coefficient of GRC below 2.0×10⁻¹² m²/s. Through three levels of protection—raw material screening, mix ratio optimization, and process control—we ensure products maintain a design life of over 50 years even in coastal and other high-salt-spray environments. In the Hainan International Convention and Exhibition Center project, our GRC roof panels withstood 10 years of coastal environment exposure, with a chloride ion penetration depth of only 0.5mm, far below the safety threshold.

Hazards of Excessive Chloride Ion Content

When chloride ion content exceeds 0.1% of the cementitious material mass, it destroys the passivation film of steel reinforcement, inducing corrosion expansion and causing the protective cover to spall. For GRC, chloride ions also accelerate the corrosion of glass fibers, reducing flexural strength by more than 30% within 5 years. Qinglong Group's accelerated tests show that specimens with excessive chloride ion content suffer a toughness loss of 50% after 300 wet-dry cycles.

Key Technologies for Chloride Ion Control

Qinglong Group uses low-chloride raw materials: cement with chloride ion content ≤0.02% and sand with chloride ion content ≤0.01%. Active admixtures such as silica fume are incorporated into the mix ratio to refine the pore structure and block penetration paths. In the production process, vacuum dewatering technology reduces the water-binder ratio to 0.30-0.35, enhancing density. We have established a raw material chloride ion testing system—every batch is tested, and those exceeding limits are rejected.

Protective Measures in Engineering Applications

In coastal areas, Qinglong Group recommends adding a surface protective layer, such as silane impregnation treatment, to reduce water absorption below 1%. Through systematic control, we ensure the chloride ion penetration safety of GRC products.