Analysis of the Mechanism and Influencing Factors of GRC Component Cracking Caused by Steel Corrosion

The durability of buildings is a core concern shared by both designers and owners, while the problem of steel reinforcement corrosion hidden inside GRC components is becoming an invisible threat to building safety and aesthetics. As an industry expert with 28 years of deep expertise in UHPC/GRC/GRG/GRP materials, Qinglong Group will provide an in-depth analysis of how steel corrosion causes GRC component cracking from the perspectives of fundamental mechanisms and practical experience, and systematically sort out the key factors affecting this process, offering the industry a technical reference that is both professional and practical.

Chain Reaction Mechanism of Steel Corrosion in GRC Components

The mechanical performance of GRC (Glass Fiber Reinforced Concrete) components relies on the synergy between glass fibers and the cement matrix, while the corrosion of embedded steel reinforcement breaks this balance. When the passivation film on the steel surface is damaged by external factors, the iron undergoes electrochemical reactions with water and oxygen, producing corrosion products that expand in volume by approximately 3-6 times. This expansion stress continuously acts on the surrounding cement matrix, leading to the initiation of microcracks. As corrosion intensifies, cracks propagate from the interior to the surface, eventually forming visible through-going cracks that not only weaken the load-bearing capacity of components but also accelerate the penetration of moisture and corrosive media, forming a vicious cycle of "corrosion-cracking-accelerated corrosion." In benchmark projects such as the Dongguan Women and Children's Activity Center, Qinglong Group's monitoring through embedded sensors found a significant positive correlation between corrosion rate and crack width—when the crack width exceeds 0.2mm, the corrosion rate increases by 2-3 times.

Multi-Dimensional Analysis of the Key Factors Affecting Corrosion-Induced Cracking of GRC Components

The material's own characteristics are the first line of defense against corrosion. Qinglong Group's R&D Center has confirmed through comparative experiments that using low-alkali sulphoaluminate cement can control the pH value of the GRC matrix at 10-11, which is more favorable for protecting the steel passivation film than ordinary Portland cement (pH>13). Meanwhile, the content and dispersion of glass fibers are also crucial—when the fiber volume content reaches 3-5% and is evenly distributed, it can effectively suppress early plastic cracks and reduce invasion channels for corrosive media. In the Nanjing East Road Century Plaza renovation project, Qinglong adopted its self-developed anti-crack GRC formula, reducing the component cracking risk by more than 40%.

The catalytic effect of environmental factors on the corrosion process cannot be ignored. In high-humidity (relative humidity >85%), high-salinity (chloride ion concentration >0.06%), or industrial atmospheric environments, the steel corrosion rate grows exponentially. The practice of Qinglong's overseas project team in Saudi Arabia shows that the corrosion rate of GRC components in coastal areas is 3-5 times that of dry inland areas. In addition, thermal stress caused by temperature fluctuations aggravates crack propagation, and freeze-thaw cycles are an "accelerator" of corrosion-induced cracking—a point that GRC projects in northern regions particularly need to pay attention to.

Quality control in the design and construction stages directly determines the effectiveness of corrosion protection. The Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018), which Qinglong Group participated in drafting, clearly stipulates that the reinforcement protective layer thickness should be no less than 25mm, and anti-corrosion measures such as epoxy resin coated reinforcement or stainless steel reinforcement should be adopted. In terms of installation technology, Qinglong's original "3D laser positioning + modular installation" technology can control component splicing errors within ±2mm, avoiding early cracks caused by installation stress. A landmark project that applied this technology reduced its later maintenance costs by 60%.

As a national high-tech enterprise and a participant in drafting GRC industry standards, Qinglong Group has always taken "creating beautiful architecture" as its mission, transforming its 28 years of full-chain experience into solutions that address industry pain points. From material formula optimization and structural design refinement to construction process innovation, every stage embodies the ultimate pursuit of durability. Choosing Qinglong GRC means not only choosing a decorative material, but also choosing a system solution verified by more than a thousand projects. In the future, Qinglong will continue to drive technological innovation in UHPC/GRC/GRG/GRP materials, providing the construction industry with safer, more durable, and more aesthetically valuable products and services.