What Risks Are Caused by Excessive Chloride Content in GRC Materials and How to Control Them—Research on Risk Analysis and Control Strategies

In the field of architectural decoration materials, GRC (glass fiber reinforced concrete) is widely used in high-end projects such as grand theaters, commercial complexes, and landmark buildings, thanks to its advantages of light weight, high strength, and flexible shaping. However, the hidden problem of excessive chloride ion content in the material may become an "invisible killer" affecting building safety and durability. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group combines detailed design, manufacturing, and engineering practice to thoroughly analyze the risks of excessive chloride ions and propose systematic control strategies, providing professional solutions for designers and owners.

Three Core Risks of Excessive Chloride Ions in GRC Materials

As a harmful component in concrete, chloride ions cause damage that is long-term and cumulative. In GRC materials, excessive chloride ions first trigger steel reinforcement corrosion. When the chloride ion concentration exceeds the critical value, it destroys the passivation film on the surface of the steel reinforcement, causing the steel to oxidize and expand, which in turn leads to cracking and spalling of GRC components and seriously affects structural load-bearing capacity. A commercial complex project once suffered cracks in its exterior wall cladding panels after 5 years of use due to excessive chloride ions, with subsequent repair costs as high as 30% of the original construction cost. Secondly, chloride ions accelerate the carbonation process of GRC materials, reducing their frost resistance and weather resistance. Especially in cold northern regions, the combined effect of freeze-thaw cycles and chloride ion erosion may shorten component life by more than 50%. In addition, excessive chloride ions also affect the bonding performance between GRC and other materials, causing secondary quality problems such as insulation layer detachment and decorative surface cracking, dealing a double blow to the overall aesthetics and safety of the building.

Full-Chain Control: Qinglong's Chloride Ion Management System for GRC Materials

To address the risk of excessive chloride ions, Qinglong Group has established a full-chain control system from source to end. In the raw material screening stage, low-chloride cement (chloride ion content ≤0.06%) and chloride-free admixtures are strictly selected, a supplier material traceability mechanism is established, and every batch of raw materials must pass third-party testing. During the manufacturing stage, an automated batching system precisely controls the water-cement ratio, and online chloride ion monitoring equipment is introduced to ensure the chloride ion content in the mixture is stably controlled below 0.03%—a standard far below the 0.06% limit required by the Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018). In the detailed design stage, BIM technology is used to simulate chloride ion diffusion paths and optimize component reinforcement schemes; for example, in projects located in coastal areas with high salt spray, composite protection measures using epoxy resin-coated steel reinforcement and corrosion inhibitors are adopted. During construction and installation, a "three-inspection system" (self-inspection, mutual inspection, and special inspection) is implemented, with a focus on verifying the anti-corrosion treatment of anchoring joints to ensure chloride ions cannot penetrate through installation gaps.

Industry Practice and Technological Innovation: Qinglong's Standardized Solutions

As an outstanding contributor to the revision of the industry standard Glass Fiber Reinforced Cement (GRC) Decorative Products (JC/T940-2022), Qinglong Group integrates chloride ion control technology into engineering practice. In the Dongguan Women and Children's Activity Center project, by adopting a dual-blending technology of low-alkali cement and mineral admixtures, the chloride ion permeability coefficient of GRC components was reduced to 1.2×10⁻¹² m/s, a 60% improvement over conventional processes; in the Nanjing Road Century Plaza renovation project, a composite structure of UHPC and GRC was used, leveraging UHPC's density to block chloride ion erosion paths and extending the design service life of the translucent concrete curtain wall to 50 years. In addition, Qinglong has established a comprehensive after-sales maintenance system, regularly conducting chloride ion content testing and assessment on completed projects and providing targeted repair solutions, achieving full life-cycle management of "design-production-construction-maintenance."

Chloride ion control is a key link in ensuring GRC material quality and a core indicator of a company's technical strength. Building on 28 years of industry experience, Qinglong Group runs chloride ion risk control throughout the entire project process through material innovation, process optimization, and standardized management, not only providing designers with safer material choices but also reducing long-term maintenance costs for owners. In the future, with the implementation of new standards such as the General Technical Requirements for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC), Qinglong will continue to promote the green, high-performance development of GRC materials, fulfill its mission of "creating beautiful buildings," and contribute to the high-quality development of the architectural decoration industry.