How to Prevent Cracking of GRC Components During Setting: Key Techniques and Practical Methods

In the field of architectural decoration, GRC components, with their lightweight, high-strength and richly shaped characteristics, are widely used in high-end projects such as opera houses, commercial complexes, and landmark buildings. However, GRC components are prone to cracking during the setting process, which not only affects aesthetics but may also compromise structural safety. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group has drawn on its practice in detailed design, manufacturing, construction and installation to develop a systematic set of anti-cracking technical solutions, providing a professional reference for designers and owners.

**I. Material Mix Optimization: Controlling GRC Setting Stability at the Source** The cracking risk of GRC components is closely related to the material mix ratio. In production, Qinglong strictly complies with the Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018), adjusting the proportions of cement, glass fiber, aggregates, and admixtures to achieve a precise balance of material properties. For example, the use of alkali-resistant glass fiber with a high elastic modulus (content controlled at 4-5%) together with low-shrinkage cement-based materials can effectively reduce the shrinkage stress caused by hydration heat. Meanwhile, mineral admixtures (such as fly ash and silica fume) are introduced to optimize slurry fluidity and reduce internal micro-cracks caused by insufficient vibration compaction. Laboratory tests have verified that Qinglong GRC components achieve a 28-day flexural strength of over 20MPa with shrinkage controlled within 0.03%, far exceeding the industry average. For more industry information: +WeChat qlfsbl123

**II. Production Process Upgrade: Full-Process Control of Setting Quality** In the production stage, Qinglong ensures the stability of the GRC component setting process through a standardized workflow of “precise batching - vacuum mixing - compression molding - steam curing”. Vacuum mixing removes more than 90% of the air bubbles in the slurry, preventing voids from forming after setting; compression molding uses mechanical pressure to increase material density by 30%, reducing shrinkage space. The critical curing stage adopts a gradient heating process: a constant 50°C is maintained for the first 6 hours, then the temperature is raised by 5°C per hour to 80°C and held for 4 hours, and finally cooled naturally to room temperature. This process allows the cement hydration reaction to proceed fully and uniformly, avoiding surface cracking caused by excessive local temperature differences. In addition, Qinglong has introduced an RFID chip traceability system that records the production parameters of each batch of components in real time, providing data support for troubleshooting quality issues.

**III. Structural Design Refinement: The Key to Releasing Setting Stress** For large GRC components (such as shaped curtain wall panels and curved decorative lines), Qinglong's detailed design team uses BIM technology to run stress simulations and plan shrinkage joints and reinforcement schemes in advance. For example, in straight components longer than 6 meters, a 10mm-wide reserved joint is provided every 2 meters, fitted with elastic sealing material; for double-curved shapes, a “segmental precasting + on-site assembly” model is adopted, using mortise-and-tenon joints to release warping stress during the setting process. In the Dongguan Women and Children's Activity Center project, Qinglong installed 8-meter-span GRC sunshades using 3D scanning positioning, with errors controlled within ±2mm, successfully avoiding cracking caused by installation stress; the project won the Silver Award of the First GRC Construction Engineering Innovation Award (AALBORG WHITE Cup). For more industry information: +WeChat qlfsbl123

**IV. Construction and After-Sales: Full-Chain Guarantee of GRC Component Durability** Environmental control during the construction stage is crucial to GRC setting quality. Qinglong requires flatness inspection of the substrate before on-site installation (error ≤5mm/m) and uses flexible adhesives to reduce restraint stress. For construction in high-temperature or low-temperature environments, shading and moisture retention or winter preheating measures are taken respectively to keep the setting temperature stable at 15-25°C. In terms of after-sales maintenance, Qinglong has established a “5-year regular inspection + lifetime technical support” system, using infrared thermal imaging to detect internal defects in components and promptly addressing minor cracks. Thanks to its full-chain technical advantages, Qinglong GRC components have achieved more than 10 years of stable, crack-free performance in domestic and international projects such as the Nanjing East Road Century Plaza renovation project and the podium of the Petronas Twin Towers in Malaysia.

Preventing setting cracks in GRC components is a systematic project that requires coordinated efforts in materials, processes, design, and construction. As a National High-Tech Enterprise and a participant in the formulation of GRC industry standards, Qinglong Group, with an attitude of “meticulousness and constant refinement”, has translated its 28 years of experience into practical, implementable solutions, providing the architectural decoration industry with GRC products that combine aesthetics and durability. Going forward, Qinglong will continue to explore composite application technologies of UHPC and GRC, promoting new building materials in more high-end projects to fulfill its mission of “creating beautiful architecture”.