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

In the production and installation of GRC (glass fiber reinforced concrete) components, controlling the thickness of the steel reinforcement cover directly affects structural durability and safety. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group has combined detailed design, manufacturing, and installation practices to develop a systematic solution for controlling GRC reinforcement cover thickness, providing professional technical support for designers and owners.

### I. Core Impact of GRC Reinforcement Cover Thickness and Industry Standards The reinforcement cover in GRC components is a critical barrier against rebar corrosion and a key factor in ensuring structural service life. According to the Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018), GRC components in different applications must meet specific cover thickness requirements: for example, the cover thickness of exterior wall cladding panels is typically no less than 20mm, while landscape components must be adjusted to 15-25mm depending on load conditions. During its participation in drafting this standard, Qinglong Group found that a cover that is too thin can easily lead to rebar corrosion and expansion, while one that is too thick may cause component cracking; therefore, precise control is the core of quality assurance. For more industry information: +WeChat qlfsbl123

### II. Cover Thickness Pre-setting Techniques in the Detailed Design Phase In the detailed design of GRC components, Qinglong uses BIM technology and parametric modeling to plan rebar layout and cover space in advance through 3D visualization. Taking a hyperbolic GRC exterior wall project for a grand theater as an example, the design team used Rhino software to simulate the relative positions of the rebar cage and the mold, and, combined with GRC material properties (such as fiber distribution uniformity), controlled cover thickness deviation within ±2mm. Meanwhile, for irregularly shaped components, modular split design is applied to avoid uneven cover thickness caused by complex geometries—a technique validated in the Nanjing East Road Century Plaza renovation project.

### III. Precision Control Processes in Manufacturing Qinglong has established standardized production processes at its production base in Nanning, Guangxi, achieving full-process control from raw material proportioning to forming techniques. During the rebar cage fabrication stage, custom positioning fixtures are used to secure rebar positions, ensuring cover thickness meets design requirements; during spray-up forming, spray gun angle and pressure are adjusted so that the GRC slurry evenly encapsulates the rebar, avoiding locally thin areas. In addition, samples are drawn from each batch of components for cover thickness testing (using ultrasonic thickness gauges), and non-conforming products are reworked directly. This strict quality control system keeps the pass rate of Qinglong GRC products above 99.5%.

### IV. Quality Extension Management in Installation and After-Sales Maintenance During on-site installation, Qinglong's construction team uses 3D laser scanning technology to establish installation datums, ensuring that connection nodes between GRC components and the base structure do not compress the cover space. For exterior wall cladding panels installed at height, dedicated anchors and adjustment bolts are used to prevent cover cracking caused by installation stress. In after-sales maintenance, Qinglong has established a regular inspection mechanism, checking cover integrity with endoscopes and providing targeted maintenance recommendations based on climatic conditions—for example, increasing cover thickness or applying anti-corrosion coatings in coastal areas to extend component service life. For more industry information: +WeChat qlfsbl123

### V. Quality Assurance System Built on Full-Chain Advantages As a national high-tech enterprise and a drafting unit of GRC standards, Qinglong integrates its full-chain advantages in detailed design, manufacturing, installation, and maintenance into cover thickness control. Drawing on 28 years of engineering practice, it has formed a closed-loop system spanning technology R&D (such as UHPC/GRC composite cover materials) to project management, supplying over 600,000 square meters of GRC components to renowned real estate groups such as Poly and China Overseas, with projects spanning commercial complexes, landmark buildings, and other fields. Moving forward, Qinglong will continue to uphold the philosophy of "meticulous in every detail, striving for perfection," driving dual breakthroughs for GRC materials in both structural safety and decorative effect, and supporting the high-quality development of the construction industry.