Does the Forming Difficulty of Double-Curved GRC Panels Differ by Thickness? An Analysis of the Dialectical Relationship Between Thickness and Process

Double-curved GRC panels of different thicknesses indeed show significant differences in forming difficulty—not a simple linear relationship, but a complex pattern of being “difficult at both ends and easy in the middle.” Based on extensive engineering practice, Qinglong Group roughly divides double-curved GRC panels into three thickness ranges: ultra-thin panels (thickness <15mm), conventional panels (thickness 15-30mm), and ultra-thick panels (thickness >30mm), each with its own unique technical challenges and process considerations.

The forming difficulties of ultra-thin double-curved panels lie in “stiffness retention” and “demolding risk.” The thinner the panel, the weaker its ability to resist deformation under its own weight and process vibration, the more dependent it is on the mold during production, and the more prone it is to cracking or permanent deformation during demolding due to adhesive forces or uneven stress release. To address this, the mix proportion needs to be optimized and the chopped fiber content increased to improve matrix toughness; meanwhile, mold design requires precise calculation of demolding angles and the adoption of pneumatic-assisted demolding systems. In an art installation project in Nanning, we successfully mass-produced 12mm-thick double-curved light-transmitting GRC panels, with the secret lying in the use of high-strength polymer fibers and vacuum-assisted forming technology.

Conventional-thickness double-curved panels are the most technically mature range, with relatively balanced production difficulty. The main difficulty lies in ensuring uniform material density throughout the panel thickness, avoiding “edge curling” or “pot bottom” phenomena caused by uneven shrinkage between the surface layer and the core layer. This needs to be addressed by controlling spraying pressure, interlayer interval time, and curing regimes. The challenges of ultra-thick double-curved panels, by contrast, shift to “internal defect control” and “hydration heat management.” As thickness increases, internal air bubbles are not easily expelled and voids tend to form; heat generated by cement hydration accumulates and may cause thermal stress cracks. To address this, we adopt techniques such as layered spraying/casting, built-in cooling water pipes, addition of ice chips, or use of low-heat cement. For example, in the fabrication of a large sculpture base in Hainan (thickness up to 50mm), high-quality forming was achieved by embedding temperature sensors to monitor the core temperature.