Special Requirements and Key Technology Analysis for the Fiberglass Mesh Laying Process of Double-Curved GRC Panels

Fibreglass Mesh Laying Technology for Double-Curved GRC Panels: An In-Depth Analysis from Technical Principles to Engineering Practice

In the field of modern architectural decoration, double-curved GRC panels have become the preferred material for high-end projects such as landmark buildings and cultural venues, thanks to their unique curved aesthetics and structural performance. As an important branch of glass fibre reinforced concrete (GRC), the core of quality for double-curved GRC panels lies in the fibreglass mesh laying process — this not only directly affects the panels' flexural strength (premium standards can reach over 20MPa) and durability, but also determines the precise realization of complex curved shapes. Qinglong Group, with 28 years of experience in GRC detailed design and production, has accumulated systematic solutions in fibreglass mesh laying technology for double-curved GRC panels. This article provides an analysis from three aspects: process particularities, key technical points, and engineering application cases.

I. Special Requirements of Double-Curved GRC Panels for Fibreglass Mesh Laying

Compared with flat GRC components, the curved form of double-curved GRC panels (with a minimum radius of curvature down to 300mm) presents three special challenges for fibreglass mesh laying: first, material compatibility — an alkali-resistant fibreglass mesh combining flexibility and strength must be selected to ensure no fibre breakage occurs during repeated bending; second, spatial positioning accuracy — the curved arcs require the mesh to be laid without wrinkles or excessive stretching, otherwise stress concentration can easily trigger cracking; third, interlayer bonding — the multi-directional loading of double-curved shapes requires the fibreglass mesh to form a “three-dimensional interlocking” structure with the cement mortar matrix to prevent later delamination.

Take, for example, a double-curved curtain wall project for a grand theatre in which Qinglong participated: its complex shape, featuring a single-curvature radius of 5.2 meters and a double-curvature variation range of 3.8-6.5 meters, required fibreglass mesh laying tolerances to be controlled within ±2mm. By adopting customized mesh fabric (mesh size 5×5mm, weight per unit area ≥450g/m²) combined with BIM technology to pre-simulate laying paths, over 3,000 double-curved panels were ultimately delivered with zero cracking.

II. Analysis of the Four Key Technologies for Fibreglass Mesh Laying

1. Curved Surface Pretreatment and Positioning Technology Molds for double-curved GRC panels mostly use GRP master molds produced by 3D carving or CNC machining. Before laying, a surface tension test is required (recommended value ≤35mN/m), along with the application of a dedicated release agent. Qinglong's original “laser dot positioning method” marks grid reference points on the mold surface and, combined with magnetic positioning fixtures, ensures that the spatial position deviation of fibreglass mesh laying is ≤1mm. This technology increased construction efficiency by 40% in a double-curved sunshade panel project for a commercial complex in Nanjing.

2. Multi-Layer Composite Laying Process In view of the load-bearing characteristics of double-curved structures, Qinglong adopts a composite process of “directional laying for the bottom layer + random laying for the surface layer”: the bottom layer uses filament fibreglass mesh laid along the principal stress direction (e.g. the radial direction of the curved surface) to improve flexural strength, while the surface layer uses cross-lapped laying to enhance overall crack resistance. Taking a 15mm-thick double-curved panel as an example, the standard laying consists of 3 layers of fibreglass mesh (1 bottom layer + 2 middle layers + 1 surface layer), with an overlap width of ≥50mm for each layer; the overlap areas are treated with a dedicated adhesive to ensure interlayer shear strength of ≥1.5MPa.

3. Dynamic Tension Control Technology Traditional manual laying is prone to localized over-tightness or looseness. Qinglong introduced CNC tension-controlled laying equipment that adjusts fibreglass mesh tension in real time via servo motors (controlled at 20-30N), combined with pressure sensor feedback, to ensure uniform tension at every point on the curved surface. In the Dongguan Women and Children's Activity Center project, this technology successfully resolved the fibreglass mesh wrinkle problem of double-curved overhanging eave panels, raising the panel pass rate from 82% to 98%.

4. Edge and Corner Reinforcement Technology For stress concentration areas such as corners and cornices of double-curved panels, a composite reinforcement scheme of “fibreglass mesh + carbon fibre fabric” is adopted: 2 additional layers of 45° diagonal fibreglass mesh are laid at the corners, and 30mm-wide carbon fibre fabric is bonded to the back. Testing shows that the flexural strength of these areas can be increased by more than 25%. This process has been incorporated into Qinglong's corporate standard “Code for Production of Double-Curved GRC Components”.

III. Engineering Quality Control and Industry Standard Practices

As a contributing unit to the “Technical Standard for Building Application of Glass Fibre Reinforced Cement (GRC)” (JGJ/T423-2018), Qinglong incorporates fibreglass mesh laying quality control into full-process management: from incoming raw materials (each batch of fibreglass mesh must be accompanied by an alkali resistance retention test report, required ≥75%), to tension calibration every 2 hours during production, to sampling tests of the bending performance of finished products (span of 20 times the thickness, deflection ≤L/200), forming a traceable quality system.

In actual engineering, the fibreglass mesh laying process for double-curved GRC panels is a comprehensive embodiment of material properties, structural mechanics, and construction technology. Qinglong's 28 years of industry experience demonstrate that only by regarding fibreglass mesh laying as the “skeleton project of curved structures” and pursuing technological innovation and refined management can the dual value of double-curved GRC materials in architectural aesthetics and structural safety be truly unleashed. From domestic landmark projects to overseas projects in Southeast Asia, Qinglong has consistently upheld the standard of “meticulousness and excellence,” promoting the innovative application of GRC materials in the field of complex architecture.