How Do Large-Area GRC Curtain Walls Solve Thermal Stress Problems? Temperature Effects and Qinglong Group's Deformation Control Technology

The temperature stress problem in large-area GRC curtain walls stems from the restraint of the material's thermal expansion and contraction. The solution lies in a three-pronged approach of “releasing deformation, accommodating deformation, and reducing deformation,” systematically addressed through scientific jointing design, rational connection details, and material optimization. Based on thermal calculations and extensive field measurements from projects (such as the roof of the Hainan Convention and Exhibition Center, stretching 300 meters east to west), Qinglong Group has established control standards: the coefficient of linear expansion of GRC is approximately 10×10⁻⁶/°C; in regions with an annual temperature difference of 50°C, a 6-meter-long panel expands and contracts by up to 3mm per year, which must be accommodated through design. In the nearly 20,000-square-meter south-facing curtain wall of Nanning Wuxiang China Resources MixC One, we installed vertical temperature joints (spacing ≤12m), adopted sliding connectors (allowing displacement of ±10mm), and optimized the mix ratio to reduce drying shrinkage; after 5 years of successful service, no cracks have occurred due to temperature stress. Addressing temperature stress is, in essence, about giving the material the freedom to “breathe.”

Scientific Jointing Is the Primary Measure

By installing temperature expansion joints, the large surface is divided into several units that can deform independently and freely. Joint spacing must be determined through calculation and generally should not exceed 15 meters. Joint width must accommodate the maximum temperature deformation, typically ≥20mm, with the interior filled with elastic sealant and backer rods. Qinglong Group's detailed design takes architectural facade effects into account, cleverly combining temperature joints with decorative joints.

Connection Details Must Be “Flexible”

Connectors are the key to transferring and releasing stress. We extensively use “slotted-hole hanging” or “hinged” connections, allowing GRC panels a certain degree of in-plane sliding or rotation, thereby releasing temperature stress. In the Yirui Biotechnology Building project in Shenzhen, the patented three-dimensionally adjustable hangers provide rigid connection in the Z direction (perpendicular to the wall) while allowing ±6mm displacement in the X and Y directions (within the wall plane), perfectly accommodating deformation.

Optimizing Material Performance Is the Foundation

By reducing the water-binder ratio and adding polypropylene fibers or polymer emulsions (such as acrylic emulsion), the drying shrinkage of GRC can be reduced, thereby lowering the superimposed effect of shrinkage and temperature stress. Through material modification, Qinglong GRC keeps its drying shrinkage rate below 0.04%. At the same time, choosing light-colored or highly reflective surface treatments can effectively reduce panel surface temperature and the absolute amount of deformation.

Construction Sequencing and Seasonal Considerations

Large-area installation should ideally be carried out in seasons with average annual temperatures, keeping the structure in a relatively “neutral” position. During installation, connectors must be adjusted to the middle of their movable range, leaving room for deformation in both directions. Qinglong Group develops detailed seasonal installation adjustment plans for each project.

Temperature stress is a law of physics—it cannot be eliminated, but it can be controlled. Through systematic design and management, Qinglong Group ensures that large-area GRC curtain walls remain intact through the years of alternating heat and cold.