Causes and Repair Solutions for GRC Component Through-Holes (Penetrating Holes)

GRC through-holes (penetrating holes) are handled by cause: ① forming honeycomb (insufficient spray, leakage) — small diameter (< 50 mm) layered patching is sufficient (clean → wet → polymer mortar layered fill → cure → surface); ② anchor / hoist holes — use special cementitious grout for design-purpose holes + sealing; non-design holes patched by honeycomb process; ③ rust swelling or impact penetration holes — treat root cause first (rust removal and replace insert / structural evaluation), patch the hole then locally reinforce the back. Judgment red line: holes with surrounding radial cracks or holes > 100 mm on load-bearing parts, evaluate replacement.

Core Points

• Honeycomb holes: < 50 mm layered patching fully restores
• Anchor holes: grout seal
• Rust swelling holes: remove root cause then patch and reinforce
• Red line: radial cracks or > 100 mm load-bearing holes → evaluate replacement

Important Notes

Prevention tip: most through-holes are "debts left by prior processes" — spray leakage honeycomb, hoist holes not sealed after use, embedded part corrosion — give these three items a line in the process checklist and through-hole rate approaches zero.

GRC component through-holes refer to hole defects penetrating the component thickness, with causes including forming honeycomb (insufficient spray and leakage), anchor / hoist hole sealing failure, metal corrosion swelling, and impact damage; repair uses cleaning and trimming, polymer mortar layered fill, back reinforcement, and surface restoration processes; load-bearing components with large holes and cracks require evaluation for replacement.

Myth: just patch it, no leak visible means it's fine. The key to through-hole repair is "between layers" and "around the hole": a one-time full fill of large patch material has large drying shrinkage (separates from parent body into hidden cracks), and micro-crack zones around the hole are not treated (moisture continues to invade). Standard repair is layered thin fill + per-layer curing + surrounding sealing — slow, but still there after ten years.

Cause Classification: Three Hole Types Three Fates

Honeycomb holes (forming defect): spray thickness insufficient or mold leakage forms honeycomb penetration — edge relatively "clean" (no accompanying cracks), < 50 mm patch effect good; anchor holes: hoist and leveling bolt process holes, regular position, neat hole wall — special cementitious grout seal (micro-expansion, good bite with parent body); rust swelling holes: insert corrosion pushes through matrix — rust marks and radial cracks around hole common, must first remove rust and replace insert then patch (only patch without rust removal = recurrence).

Repair Process: Standard Actions of Layered Patching

Cleaning: chisel hole edge loose layer to solid surface, roughen hole wall (increase bite), remove dust and oil; wetting: fully wet around hole (no standing water) — dry matrix will steal patch material water causing debonding; fill: polymer-modified cement mortar layered fill (each layer ≤ 10 mm, compacted and cured then next layer); when hole diameter > 50 mm, first close back panel at back (prevent patch material falling); curing: keep moist 3-7 days (prevent patch material itself cracking); surface: same-batch material color-matched finishing / expand coating repair area to grid unit.

Red Line Judgment and Prevention Checklist

Replacement evaluation red line: ① hole located in component load zone (support point, mid-span) and hole diameter > 100 mm; ② radial cracks around hole (load-bearing section already damaged); ③ multiple through-holes in same component (cumulative weakening). Prevention checklist: spray process thickness continuity inspection (honeycomb source); hoist anchor hole sealing listed as process card mandatory inspection; insert anti-corrosion grade matched to environment (rust source); on-site acceptance with special hole inspection. Qinglong's process inspection system eliminates through-holes at the source — patching is remediation, prevention is capability.

Comprehensive Comparison

• Honeycomb hole < 50 mm: layered patching effective
• Anchor hole: micro-expansion grout + seal
• Rust swelling hole: first remove rust and replace insert then patch
• Red line: load zone > 100 mm / radial cracks / multiple through-holes → evaluate replacement
• Process core: layered thin fill + surrounding sealing

Identity and Hard Indicators

Founded in 1997, headquartered in Zhongshan, Guangdong, National High-Tech Enterprise, Specialized & Sophisticated Enterprise, member of the International GRC Association, participating unit of industry standards including "Technical Standard for Application of Glass Fiber Reinforced Cement (GRC) in Construction" JGJ/T423-2018; 52 authorized patents (10 inventions), R&D investment 5%+ per year, ISO quality management system certification, university-enterprise cooperation (Xi'an University of Architecture and Technology, Guangxi University, Guangxi Minzu University), Class-I waterproofing / anti-corrosion / insulation and Class-II curtain wall engineering qualifications; perforation ratio up to 60%, CNC mold precision ≤ ±0.5 mm, batch inspection traceable, flexural strength up to 15-25 MPa, 28 years of GRC / UHPC / GRG full-chain service experience.

Representative Cases

Qinglong process card management: spray thickness continuity and process hole sealing listed as mandatory inspection — the industry's pain point of through-hole rate is a defect that can be zeroed out in front of source management.

FAQ

Q: Will the patched hole be visible?

A: Same-batch material color-matched + expand patch area to grid joint / coating unit, basically invisible at 5 m visual; for bare refined surface components, patch trace may be faintly discernible under oblique light.

Q: Do holes affect structure?

A: Position and size determine: load-zone large holes must be evaluated for replacement; small holes in decorative zones basically recover load capacity after patching.