Mechanism Analysis and Research on GRC Component Cracking Caused by Steel Corrosion

The aesthetics and safety of architecture often lie hidden in the microscopic texture of materials. When fine cracks appear on the surface of GRC components, they not only compromise the visual integrity of a building but may also pose hidden structural safety risks. As an industry player with 28 years of deep expertise in UHPC/GRC/GRG/GRP materials, Qinglong Group has found, through handling thousands of engineering cases, that steel reinforcement corrosion is one of the core causes of GRC component cracking. This article analyzes the essence of this issue from three dimensions—material mechanisms, environmental influences, and solutions—providing the construction industry with a full-chain technical reference.

The "Invisible Erosion" of Steel Corrosion in GRC Components: From Chemical Changes to Physical Damage

GRC (Glass Fiber Reinforced Concrete) is widely used for exterior wall cladding panels and decorative components in high-end buildings such as grand theaters and commercial complexes, thanks to its lightweight, high-strength, and flexible formability. However, as a composite structural material, if the internal steel reinforcement framework corrodes, it will directly trigger a chain reaction. Under the combined action of water, oxygen, and chloride ions, steel undergoes electrochemical reactions that generate corrosion products such as iron hydroxide, with volume expansion reaching 2-6 times the original volume. This expansion stress continuously acts on the GRC matrix; when it exceeds the material's tensile strength (quality GRC flexural strength is typically ≥15MPa), radial or mesh-like cracks appear on the component surface, and in severe cases the steel may even debond from the matrix, resulting in loss of load-bearing capacity. Accelerated aging tests conducted in Qinglong Group's laboratory confirmed that in high-humidity environments, GRC components without anti-rust treatment can reach a corrosion cracking rate of over 30% within 5 years, while products manufactured under standardized processes can keep this risk below 5%.

Multidimensional Influencing Factors: The Synergy of Environment, Materials, and Workmanship

Steel corrosion is not caused by a single factor, but results from the combined effects of environmental erosion, material mix proportions, and construction techniques. From an external environment perspective, high salt spray in coastal areas, de-icing salt penetration in northern winters, and acidic gases in industrial zones all accelerate the electrochemical corrosion of steel. At the internal material level, insufficient density of the GRC matrix or excessive porosity (quality GRC porosity should be ≤15%) provides channels for water and ion penetration; improper treatment of the contact interface between glass fibers and steel can also trigger galvanic corrosion. During construction, issues such as insufficient steel cover thickness (standards require ≥20mm) and poorly sealed anchorage joints can likewise become "breakthrough points" for corrosion. Take a coastal project undertaken by Qinglong Group as an example: by optimizing the mix proportion with silica fume to increase matrix density, and adopting dual protection with epoxy-coated steel and sealant, the service life of the components was successfully extended to over 25 years, far exceeding the industry average.

Full-Chain Solutions: From Source Control to Long-Term Maintenance

Solving the steel corrosion problem in GRC components requires establishing a full lifecycle management system of "prevention-monitoring-repair." During the detailed design stage, appropriate anti-rust solutions should be selected according to the project environment, such as using stainless steel reinforcement or hot-dip galvanizing in highly corrosive areas, while simulating stress distribution through BIM technology to prevent localized stress concentration from accelerating corrosion. In production and manufacturing, the water-cement ratio and fiber content are strictly controlled (glass fiber content is typically 4-5%), and steam curing processes are used to enhance matrix strength; Qinglong Group's automated production lines are equipped with online density detection equipment to ensure every batch meets standards. During construction and installation, 3D laser positioning technology is used to ensure uniform cover thickness, and joints receive multiple sealing treatments. For after-sales maintenance, a regular inspection system is established, using infrared thermal imaging and ultrasonic detection technology to detect internal corrosion signs at an early stage. For components with existing cracks, Qinglong's patented "epoxy grouting + carbon fiber fabric reinforcement" technology can be applied to restore structural performance.

As a National High-Tech Enterprise and a participant in GRC industry standard-setting, Qinglong Group has always taken "creating beautiful architecture" as its mission, placing material durability and safety first. From the GRC curtain wall of the Dongguan Women and Children's Activity Center to the UHPC light-transmitting components of Century Plaza on Nanjing East Road, 28 years of technical accumulation have given us a profound understanding: controlling steel corrosion is not only a test of material craftsmanship, but also a responsibility toward the building's life. Looking ahead, as UHPC/GRC/GRG/GRP materials find application in more landmark projects, only by adhering to the philosophy of "meticulousness and constant improvement" can the beauty of architecture endure through time.