How to Control Rebar Cover Thickness in GRC: Key Technologies and Quality Assurance Measures Explained

In the field of architectural decoration, GRC materials, with their lightweight, high-strength properties and rich modeling capabilities, are widely used in high-end buildings such as grand theaters and commercial complexes. As a core indicator of GRC component durability, the steel reinforcement cover thickness directly relates to the safety and service life of building structures. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP, Qinglong Group will provide an in-depth analysis of the key control technologies for steel reinforcement cover thickness in GRC, covering material properties, process control, and quality assurance.

GRC Steel Reinforcement Cover Thickness: Material Properties and Design Basis

GRC (Glass Fiber Reinforced Concrete) is composed of cement, glass fibers, aggregates, and other materials. Its steel reinforcement cover thickness must meet both structural load-bearing and durability requirements. According to the Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018), together with the industry specifications that Qinglong Group participated in formulating, the cover thickness is generally determined comprehensively based on the environment in which the component is used (e.g., humid or freeze-thaw regions), the design service life (generally over 50 years), and the rebar diameter. For example, for GRC components used as exterior wall cladding panels, a cover thickness of no less than 25mm is recommended to resist UV rays and rain erosion. This standard is strictly implemented in Qinglong's Nanning production base, which has an annual capacity of 600,000 square meters.

Full-Process Control: Technical Essentials from Detailed Design to Construction and Installation

During the detailed design stage, Qinglong adopts BIM technology and parametric design software (such as Rhino and Grasshopper) to precisely position the steel reinforcement cage relative to the mold, ensuring uniform cover thickness. In the production stage, automated material dispensing machines and vibration molding processes are used to avoid uneven cover thickness caused by material accumulation. Meanwhile, a composite reinforcement system of ribbed rebar and fiber mesh is adopted to enhance the bond between the rebar and the GRC matrix, reducing the risk of cover cracking. During construction and installation, the application of 3D laser scanning technology enables millimeter-level positioning accuracy; combined with Qinglong's patented modular anchoring system (Patent No.: ZLXXXXXX), it effectively prevents cover damage from compression during installation.

Quality Assurance System: Testing, Traceability, and Industry Standard Practices

Qinglong has established a full-cycle quality traceability system covering “raw materials - production - installation”. Each batch of GRC components is tested for cover thickness with an ultrasonic thickness gauge, and RFID chips are embedded to record production information. As a National High-Tech Enterprise and the Vice Chairman Unit of the China GRC Association, Qinglong participated in the revision of Glass Fiber Reinforced Cement (GRC) Decorative Products (JC/T940-2022), which clearly specifies the testing methods and qualification standards for cover thickness. For example, in the Nanjing East Road Century Plaza renovation project, through strict cover thickness control, Qinglong's translucent concrete GRC components achieved 15 years of crack-free durability, winning the Silver Award of the AALBORG WHITE Cup UHPC Construction Engineering Innovation Award.

The control of steel reinforcement cover thickness is a key bridge for GRC materials to move from “artistic form” to “structural safety”. Backed by 28 years of professional experience, Qinglong Group deeply integrates material science, digital technology, and engineering practice, not only providing designers with broader creative space but also creating architectural works that combine aesthetics and durability for owners. In the future, with the development of UHPC/GRC composite technology, Qinglong will continue to drive the upgrading of industry standards. With the mission of “creating aesthetic architecture”, Qinglong will help more landmark projects achieve a perfect unity of safety and art.