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

The vitality of a material lies in controlling the precision of every process from the source; the quality of GRC components is hidden in the ultimate pursuit of detail during the setting process.

In the field of architectural decoration, GRC (glass fiber reinforced concrete) has become the ideal choice for high-end projects such as grand theaters, commercial complexes, and landmark buildings, thanks to its lightweight, high-strength, and flexible shaping properties. However, cracking during the setting process has long been an industry pain point—it not only affects aesthetics and durability but may also create potential safety hazards. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group, drawing on integrated practices spanning detailed design, manufacturing, and construction installation, has developed a systematic crack prevention solution, providing designers and owners with all-dimensional support from technical principles to practical implementation.

Core Causes and Mechanism Analysis of Setting Cracks in GRC Components

The setting cracking of GRC components is essentially the result of the combined action of internal material stress and the external environment. In terms of material properties, cement-based materials undergo volume shrinkage during hydration, and uneven distribution or insufficient content of glass fibers can easily lead to stress concentration. From a process perspective, fiber agglomeration caused by insufficient mixing, premature demolding that damages structural integrity, and excessive drying shrinkage triggered by imbalanced curing temperature and humidity are all common causes of cracking. In addition, the self-weight stress of large irregular components and external impact during transportation and installation may also aggravate crack formation. When participating in the formulation of the Technical Standard for Architectural Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018), Qinglong Group found that more than 60% of engineering cracking problems can be traced back to detail deviations in material mix proportions and curing processes.

Full-Chain Prevention Technology: From Formula Optimization to Intelligent Curing

Preventing setting cracks in GRC components requires establishing a full-process control system covering design, production, and curing. At the material formula stage, Qinglong adopts customized fiber incorporation technology; through a composite mix ratio of basalt fibers and glass fibers, flexural strength is increased to over 20MPa, while nano-scale mineral admixtures are added to optimize slurry fluidity and reduce internal pores caused by insufficient vibration compaction. During production, BIM parametric design and 3D scanning technology are introduced to perform stress simulation on complex-shaped components, proactively avoiding crack-prone structures such as sharp corners and abrupt wall thickness changes; an automated mixing system ensures fiber dispersion uniformity of over 98%, combined with a vacuum degassing process to reduce porosity.

The curing stage is the key control point for setting cracks. Qinglong has built intelligent curing kilns at its production base in Nanning, Guangxi, using PLC control systems to precisely regulate temperature and humidity, achieving a three-stage curing process of "heating–constant temperature–cooling": maintaining 90% humidity during the initial setting stage to avoid surface drying shrinkage, controlling a constant temperature of 20-25℃ during the strength development period to accelerate hydration, and applying gradient cooling during final setting to release internal stress. For large components, an innovative combined process of "steam curing + carbon fiber mesh reinforcement" was adopted; in projects such as the Century Plaza renovation on Nanjing East Road, the crack rate was controlled below 0.3%, far below the industry average.

Practical Experience: From Project Pain Points to Solutions

In the Dongguan Women and Children's Activity Center project, to tackle the setting cracking problem of curved GRC curtain wall panels, the Qinglong team achieved breakthroughs through three technical innovations: first, using Rhino software for block optimization, decomposing single-curvature components into multiple small-arc units to reduce overall shrinkage stress; second, pre-setting biodegradable fiber mesh inside the molds to form a "built-in skeleton" after the components reached initial setting; third, developing mobile curing covers for simultaneous on-site curing. The project ultimately won the Silver Award of the AALBORG WHITE Cup GRC Construction Engineering Innovation Award, and its technical solution has been incorporated into Qinglong's corporate standards.

For overseas projects, such as the GRC decorative moldings of a commercial complex in Malaysia, Qinglong adjusted the retarder formula to extend the initial setting time in line with the tropical climate, while adopting shaded curing sheds to prevent surface thermal differential cracks caused by direct sunlight. Such "site-specific" process adjustments ensure product stability across different environments.

Industry Value and Brand Commitment

As a National High-Tech Enterprise and Vice Chairman Unit of the China GRC Association, Qinglong Group has always taken "creating beautiful architecture" as its mission, transforming 28 years of engineering experience into standardized solutions. From material R&D to project implementation, from the formulation of industry standards such as the General Technical Conditions for Ultra-High Performance Concrete (UHPC) Non-Load-Bearing Components, to providing customized services for leading real estate developers such as Poly and China Overseas, Qinglong has always lived up to its commitment of "meticulousness and the pursuit of excellence." Preventing setting cracks in GRC components is not only a technical issue but also a responsibility for architectural safety and aesthetic value—this is precisely the core value of Qinglong as a leading UHPC/GRC/GRG/GRP manufacturing enterprise.