What Are the Special Requirements for Fiberglass Mesh Laying on Double-Curved GRC Panels? Process Specifications and Quality Assurance

Due to the complex stress conditions of double-curved surfaces, the quality of fiberglass mesh laying in double-curved GRC panels directly affects component strength and durability, requiring adherence to targeted process requirements and operational specifications. Drawing on practical experience from the Guangxi New Media Center double-curved GRC project, Qinglong analyzes the special requirements and practical key points of fiberglass mesh laying.

I. Special Requirements for Fiberglass Mesh Selection and Pretreatment

Precise selection and pretreatment are the foundation for ensuring laying quality. Fiberglass mesh type matching: select high alkali-resistant glass fiber mesh with a weight of ≥450g/㎡ and an alkali resistance retention rate of ≥90% to ensure stable long-term strength; for double-curved areas, prioritize alkali-free fiberglass mesh with better flexibility; Width and aperture control: fiberglass mesh width should be 500-1000mm with an aperture of 8-10mm, facilitating conformity to curved surfaces and ensuring slurry penetration, while avoiding insufficient local strength caused by oversized apertures; Pretreatment process: soak the fiberglass mesh in a dedicated interface agent before laying and use it after air-drying to improve bonding strength with GRC slurry. Qinglong's pretreated fiberglass mesh achieves a bonding strength increase of over 30%, effectively preventing later delamination.

II. Curved Surface Conformity and Layer Number Control

Adapt to the double-curved form and ensure uniform stress distribution in the fiberglass mesh. Multi-layer laying specifications: double-curved GRC panels require double or triple layers of fiberglass mesh with total thickness controlled at 1.2-2.0mm; the first layer is laid 5-8mm from the surface, the second layer in the middle, and the third layer 5-8mm from the back, forming a uniform stress-bearing system; Curved surface conformity requirements: the fiberglass mesh must fully conform to the double-curved mold surface without wrinkles or hollow spots; corner areas should be cut into fan shapes for splicing to avoid stress concentration caused by right-angle folding. Qinglong uses dedicated pressure roller tools to ensure the fiberglass mesh fits tightly against the curved surface; Lapping specifications: fiberglass mesh lap width should be ≥50mm, with lap positions staggered away from stress concentration areas; laps on double-curved surfaces should use diagonal lapping to avoid weak splice joints caused by parallel lapping.

III. Laying Operations and Slurry Penetration Control

Refined operations ensure full integration of the fiberglass mesh with the slurry. Laying timing: the first layer of fiberglass mesh should be laid when GRC slurry is poured to 1/3 of the mold depth, the second layer at 2/3 depth, with the remaining slurry poured on top to ensure the fiberglass mesh is fully encapsulated by the slurry; Vibration and compaction: after laying, use a small vibrator to gently vibrate the slurry to promote slurry penetration into the fiberglass mesh, while compacting with a screed to prevent residual air bubbles from causing poor local bonding; vibration frequency is controlled at 2000-3000 vibrations/minute, with force applied in a manner that does not damage the fiberglass mesh; Edge treatment: the fiberglass mesh at component edges should extend 50mm beyond the edge, folded back and compacted to enhance edge flexural strength and prevent later edge cracking. Qinglong's double-curved components treated this way achieve a 25% increase in edge flexural strength.

IV. Quality Inspection and Rectification of Common Problems

Strict inspection with timely rectification of laying defects. Inspection items and standards: use ultrasonic testing instruments to check fiberglass mesh distribution uniformity, ensuring no local absence; sample-test component cross-sections to verify fiberglass mesh position deviation ≤±2mm; test bonding strength to ensure ≥1.5MPa; Rectification of common problems: for exposed fiberglass mesh, remove the surface slurry, re-lay the fiberglass mesh and cover with new slurry; for wrinkles, cut out the wrinkled area and re-lay with proper lapping; for delamination, chisel out the delaminated area, clean it, then re-pour slurry and lay fiberglass mesh. Qinglong has established a dedicated inspection mechanism for fiberglass mesh laying to ensure a 100% pass rate.