What Risks Can Excessive Chloride Ion Content in GRC Materials Cause? How to Control It?

Excessive chloride ion content in GRC will cause serious durability problems, especially the risk of electrochemical corrosion to reinforcing fibers and metal embedded parts. Standards require that Cl- content not exceed 0.1% of the cementitious material mass; exceeding this limit will lead to a sharp decline in fiber strength and rust-induced expansion of metal parts.

Experimental data show that when Cl- content increases from 0.1% to 0.3%, the strength retention rate of alkali-resistant glass fibers in alkaline environments drops from 80% to 45%, and the corrosion rate of embedded steel parts increases 5-fold. Qinglong GRC ensures that Cl- content remains stable below 0.06% through raw material chloride testing, mix proportion optimization, and production process control. Testing after 5 years of use in a coastal project showed a fiber strength retention rate of 85% with no corrosion of embedded parts, proving the effectiveness of these controls.

Chloride Ion Source Control

Sand in raw materials: Cl- ≤ 0.01%; mixing water: Cl- ≤ 200mg/L; admixtures: Cl- ≤ 0.1%. These controls eliminate chloride ion introduction at the source.

Mix Proportion Optimization Measures

Adding silica fume (8%-10%) to solidify free chloride ions; using mineral powder (5%-8%) to bind chloride ions; controlling the water-binder ratio at 0.30-0.35 to reduce capillary pores. These measures reduce chloride ion activity.

Strict Production Process Control

Prohibiting the use of sea sand and chloride-containing early-strength agents; testing Cl- in equipment cleaning water; curing water Cl- ≤ 200mg/L. These controls prevent contamination during production.

Enhanced Protective Measures

Surface coatings to block chloride ion penetration; joint sealing to prevent intrusion; regular inspections for timely detection and treatment. These measures provide additional protection.

Chloride ion control requires systematic measures. Qinglong GRC has established a comprehensive control system to ensure product durability and safety.