What Are the Consequences of Not Applying Anti-Rust Treatment to Embedded Steel Bars After Welding?

Failure to apply anti-rust treatment after welding the embedded steel bars of GRC components leads to four serious consequences—steel bar corrosion, reduced connection strength, GRC component cracking and falling off, and increased maintenance costs—and may even cause safety accidents. Qinglong emphasizes that anti-rust treatment must be carried out in accordance with standards after welding; multiple projects that strictly implemented anti-rust processes have had no such hidden dangers.

1. Steel Bar Corrosion: A Root Hidden Hazard to Structural Safety

Welded steel bars without anti-rust treatment corrode rapidly. Corrosion rate: welded steel bars exposed to air show obvious corrosion within 6 months in humid environments, and can corrode within 3 months in coastal salt-spray environments; Qinglong's test data show that welded steel bars without anti-rust treatment reach a corrosion depth of ≥0.5mm within 1 year. Corrosion product expansion: after corrosion, steel bars expand 2-3 times in volume, squeezing the surrounding GRC matrix and causing internal stress in the GRC; in Qinglong's simulation tests, corroded steel bars caused microcracks of over 0.3mm in the GRC. Welded areas corrode preferentially: the high temperature of welding destroys the passivation film on the steel bar surface, and corrosion at welded joints is 2-3 times faster than at ordinary areas; Qinglong's inspection found that after 6 months, the corrosion level of welded joints without anti-rust treatment was 2.5 times that of ordinary areas.

2. Reduced Connection Strength and Component Cracking and Falling Off

Corrosion gradually leads to connection failure and component damage. Connection strength decline: steel bar corrosion reduces the bond strength between the steel bar and the GRC matrix, with bond strength dropping 30% within 1 year and more than 50% within 3 years; in Qinglong's tests, the bond strength of welded steel bars without anti-rust treatment after 2 years was only 45% of the initial value. GRC component cracking: expansion of corrosion products squeezes the GRC, producing through cracks (width ≥0.3mm); rainwater infiltration accelerates corrosion and crack growth; in Qinglong's project cases, components without anti-rust treatment showed obvious cracks within 2 years. Risk of components falling: when steel bars are severely corroded (cross-section loss ≥20%), the connection strength can no longer bear the weight of the GRC components, making high-altitude falling likely and causing safety accidents; such cases occur from time to time in the industry.

3. Increased Maintenance Costs and Shortened Service Life

Failure to apply anti-rust treatment greatly increases later costs and shortens service life. Maintenance costs: after corrosion, components must be removed, steel bars replaced, and reinstalled, and maintenance costs are 3-5 times the initial installation cost; Qinglong estimates that repairing a 1,000-square-meter GRC curtain wall due to steel bar corrosion costs over one million yuan. Shortened service life: GRC components without anti-rust treatment have a service life of only 1/3 that of standard-treated components (about 5-8 years), while components with standard anti-rust treatment can last 20-30 years; the service life of Qinglong's standard-treated projects has been verified to exceed 10 years. Safety risk costs: falling components may cause casualties and property damage and lead to legal disputes, with extremely high hidden costs. Qinglong's recommendation: remove welding slag immediately after welding, sandblast to remove rust (grade ≥Sa2.5), apply two coats of anti-rust paint + one top coat, and seal joints with sealant, avoiding the consequences of corrosion at the source.