Exploring Solutions to Thermal Stress Problems in Large-Area GRC Curtain Walls

Thermal stress is the "invisible killer" of GRC curtain walls; 28 years of industry experience shows how to systematically solve this technical challenge.

As modern architecture pursues both aesthetics and functionality, large-area GRC curtain walls have been widely applied in high-end buildings such as grand theaters and commercial complexes, thanks to their flexible styling and rich textures. However, the thermal expansion and contraction characteristics of glass fiber reinforced concrete (GRC) make it prone to thermal stress under drastic ambient temperature changes, potentially leading to curtain wall cracking, deformation, and other quality risks. As an industry leader with 28 years of deep expertise in UHPC/GRC/GRG/GRP materials, Qinglong Group has drawn on practical experience from hundreds of large-scale projects to develop a systematic thermal stress solution covering material formulation, structural design, and construction techniques.

Causes of Thermal Stress in GRC Curtain Walls and Industry Pain Points

GRC material is a composite of cement-based binders, glass fibers, and aggregates, with a linear expansion coefficient of approximately 10×10⁻⁶/℃. Under environmental factors such as solar temperature differences and annual temperature variations, curtain wall panels undergo significant thermal expansion and contraction. When this deformation is restrained, internal thermal stress develops—one of the main causes of GRC curtain wall cracking. Industry research shows that more than 60% of GRC curtain wall after-sales issues are related to improper thermal stress control, and this problem is particularly prominent in China's severe cold northern regions and the high-temperature, high-radiation southern areas. As a National High-Tech Enterprise, Qinglong Group listed thermal stress control as a core technical point when participating in drafting the Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018).

Material Innovation: Enhancing GRC Crack Resistance at the Source

Solving the thermal stress challenge starts with material formulation. Qinglong Group's R&D center optimized cement-based material ratios and introduced mineral admixtures and modified additives, controlling the elastic modulus of GRC material within 25-30 GPa to reduce rigidity while improving toughness. For glass fibers, an alkali-resistant glass fiber mesh and chopped strand composite reinforcement system is adopted, raising the material's flexural strength to over 20 MPa and increasing elongation at break by 15%, effectively relieving stress concentration caused by thermal deformation. In addition, micro-expansion compensation is achieved by adding compound expansion agents to further offset thermal shrinkage effects. These technical innovations enable Qinglong GRC products to achieve a strength loss rate below 5% after 50 freeze-thaw cycle tests, far exceeding industry standards.

Structural Optimization: Design Wisdom for Dynamic Thermal Stress Release

During the curtain wall structural design phase, Qinglong Group uses BIM technology to build temperature field simulation models, accurately simulating thermal stress distribution across different climate zones. By adopting a "flexible connection + joint control" design strategy, temperature expansion joints 10-15 mm wide are set between curtain wall panels, combined with a slidable bracket system that allows panels to expand and contract freely within a ±30 mm range. For oversized GRC curtain walls (single panel area exceeding 10 ㎡), an innovative "unitized modular" design breaks the overall structure into independent load-bearing units, absorbing thermal deformation through the three-dimensional adjustment capability of connector fittings. This design approach was successfully applied in the Nanjing East Road Century Plaza renovation project, which adopts a translucent GRC curtain wall system. After two summers of high-temperature testing, no cracking has occurred.

Construction Control: Full-Process Implementation of the Thermal Stress Solution

Construction is the critical implementation stage for thermal stress control. Qinglong Group has established a "three inspections, three tests" construction quality management system: testing elastic modulus and thermal expansion coefficient before materials enter the site to ensure performance indicators meet design requirements; using 3D laser scanning technology during installation to keep panel positioning errors within ±2 mm; and conducting temperature cycle monitoring after completion, recording panel deformation data continuously for 72 hours. For high-temperature season construction, a "morning and evening installation, midday curing" work schedule is adopted to prevent sudden surface temperature rises of GRC components caused by direct sunlight exposure. At the Nanning production base in Guangxi, Qinglong operates intelligent production lines with an annual capacity of 600,000 square meters. Through constant temperature and humidity curing processes, the moisture content of factory-shipped components is kept below 8%, reducing additional stress caused by later drying shrinkage.

As Vice Chairman Unit of the China GRC Association, Qinglong Group has always upheld the mission of "creating beautiful architecture," integrating thermal stress control technology into the full life-cycle management of GRC curtain walls. From material R&D to project delivery, from domestic landmark projects to overseas markets in Southeast Asia, Qinglong's 28 years of professional expertise prove that with scientific material innovation, precise structural design, and strict construction control, thermal stress issues in large-area GRC curtain walls are fully controllable. Looking ahead, Qinglong will continue to focus on technical breakthroughs in UHPC/GRC/GRG/GRP materials, providing architects and owners with more innovative and reliable architectural decoration solutions, and helping create more architectural masterpieces that stand the test of time.