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

In the field of architectural decoration, GRC components are widely used in exterior wall cladding panels, decorative lines, and landscape elements of high-end projects such as grand theaters, commercial complexes, and landmark buildings, thanks to their advantages of light weight, high strength, and rich styling. However, the cracking of GRC components caused by steel bar corrosion has long been a key challenge affecting their durability and safety. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group draws on detailed design, production, and engineering practice to thoroughly analyze the underlying mechanisms and core influencing factors of this problem, providing professional solutions for designers and owners.

GRC components are composite materials made of glass fiber, cement matrix, and a steel reinforcement skeleton. Steel bars, as the main load-bearing elements, corrode essentially as a result of the combined action of electrochemical corrosion and physical expansion. When components are exposed to damp, salt-spray-heavy, or high-humidity environments, moisture and corrosive media such as chloride ions and carbon dioxide penetrate through the pores of the GRC matrix to the surface of the steel bars, destroying the passive film and triggering electrochemical reactions that produce corrosion products (such as iron hydroxide and iron oxide) with volumes several times larger. This expansion pressure continuously acts on the surrounding cement matrix; when it exceeds the tensile strength of the GRC material, cracks appear on the component surface along the direction of the steel bars. In severe cases, it can even cause the cover layer to spall and the steel bar cross-section to shrink, directly threatening structural safety. For more industry information: + WeChat qlfsbl123

The factors affecting steel bar corrosion and GRC component cracking can be grouped into three categories: material properties, environmental conditions, and construction techniques. At the material level, the compactness of the GRC matrix is key—if the bond at the interface between the cement paste and glass fiber is poor or the porosity is too high, the penetration of corrosive media will be accelerated; insufficient thickness of the steel bar cover layer or the use of ordinary low-carbon steel instead of corrosion-resistant steel bars will also shorten the corrosion incubation period. Among environmental factors, temperature changes, humidity fluctuations, and corrosive ions in industrial atmospheres (such as Cl⁻ and SO₄²⁻) are the main triggers; for example, the high-salt-spray environment of coastal areas significantly accelerates the rate of steel bar corrosion. The impact of the construction phase is equally significant: mechanical damage during steel bar tying, air bubble defects caused by insufficient concrete vibration, or early shrinkage cracks caused by improper later curing all provide "channels" for corrosive media.

In response to the above mechanisms and influencing factors, Qinglong Group has built a systematic prevention and control framework within the full life cycle management of GRC components. During the detailed design stage, BIM technology is used to optimize steel bar layout and cover layer thickness, and epoxy-coated or stainless steel bars are selected to enhance corrosion resistance; in the manufacturing stage, a high-density cement matrix formula and vacuum grouting process are adopted to reduce porosity and ensure coordinated load-bearing between the steel bars and the matrix; during construction and installation, 3D laser scanning positioning technology ensures precise alignment of components and reduces micro-cracks caused by installation stress; in the after-sales maintenance stage, a regular inspection mechanism is established to monitor the degree of steel bar corrosion through the electromagnetic induction method, combined with Qinglong's proprietary repair materials and techniques to promptly repair cracked components.

As a company that participated in drafting the Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018), Qinglong Group has always upheld its mission of "creating beautiful architecture," transforming 28 years of engineering experience into deep mastery of GRC material performance. From the GRC shaped components at the Dongguan Women and Children's Activity Center to the light-transmitting concrete project at Century Plaza on Nanjing East Road, Qinglong has effectively solved the problem of steel bar corrosion cracking through material innovation and process upgrades, providing customers with GRC solutions that combine aesthetic value with structural safety. Going forward, Qinglong will continue to focus on the technological R&D of UHPC/GRC/GRG/GRP materials, striving to become a world-class leading manufacturer of architectural decoration materials.