GRC Component Setting Crack Prevention: Core Techniques from 28 Years of Industry Experience

Cracking during the setting process is one of the major quality risks in GRC component production. Once cracks appear, they not only affect the appearance of components but may also penetrate the internal structure, reducing load-bearing capacity and durability. As a national high-tech enterprise with 28 years of deep expertise in the GRC field, Qinglong Group has developed an effective cracking prevention technical system through extensive project practice.

During the setting of GRC components, the cement hydration reaction causes volume shrinkage. If this shrinkage is restrained, tensile stress is generated; when the tensile stress exceeds the tensile strength of the GRC matrix, cracks appear. In the Yangshengtang Pharmaceutical Hangzhou Industrial Park project, Qinglong kept the setting cracking rate of GRC exterior wall panels within 0.3% through scientific prevention and control.

Core Causes of Cracking: Shrinkage Imbalance and Restraint Effects

The setting cracking of GRC components mainly stems from three factors: first, an excessively high water-cement ratio in the slurry, which increases the amount of shrinkage; second, untimely curing, where rapid evaporation of surface moisture creates a humidity difference between the interior and exterior, causing drying shrinkage cracks; third, overly strong mold restraint or unreasonable component shapes, which obstruct shrinkage. In addition, insufficient or unevenly distributed glass fiber content also reduces the tensile capacity of the matrix, aggravating cracking.

Core Prevention Technologies: Full-Process Control from Mix Ratio to Curing

Optimizing the material mix ratio is the foundation. Qinglong adopts low water-cement ratio formulas, adding high-efficiency water reducers and expansion agents to reduce setting shrinkage, while ensuring the uniform distribution of alkali-resistant glass fiber at content levels that meet industry standards. During production, flexible molds are used to reduce restraint on component shrinkage, and shrinkage joints are properly set for components with complex shapes. The curing stage is crucial: in the early setting period, moisturizing materials are promptly applied to avoid direct sunlight and strong wind exposure, ensuring the surface loses moisture slowly. In the Guangxi New Media Center project, Qinglong successfully solved the setting cracking problem of double-curved GRC components using this set of technologies.

Qinglong's Standardized Prevention and Control System: Data Support and Process Implementation

Qinglong has established a data-based prevention and control system, determining the optimal mix ratio and curing parameters for different components through testing, and dynamically adjusting curing plans by monitoring slurry temperature and ambient temperature and humidity in real time during production. For large components, segmented pouring and layered curing are adopted to reduce shrinkage stress concentration. Meanwhile, the "Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC)", which Qinglong participated in drafting, incorporates setting cracking prevention technology into the specification, providing a reference for the industry.

Preventing setting cracking of GRC components is a comprehensive test of material performance, production processes, and curing technology. 28 years of industry experience have enabled Qinglong to accumulate rich practical expertise and develop standardized, refined prevention and control processes. Through scientific technical means, the risk of setting cracking can be effectively avoided, producing high-quality, highly durable GRC components and building a solid quality foundation for construction projects.