Mechanism and Impact Analysis of Steel Corrosion Induced Cracking in GRC Components

In the field of architectural decoration, GRC components are widely used in various building projects thanks to their lightweight, high-strength, and richly formable qualities. However, cracking of GRC components caused by steel reinforcement corrosion not only affects the building's aesthetics but also poses a potential threat to structural safety. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group will provide an in-depth professional analysis of the mechanisms, impacts, and countermeasures for this issue, offering reliable solutions for designers and building owners.

I. Internal Mechanism of GRC Component Cracking Caused by Steel Reinforcement Corrosion

GRC components are composed of glass fibers, a cement matrix, and a steel reinforcement skeleton, in which the steel reinforcement serves as the primary load-bearing element, and its corrosion process is closely related to the properties of cement-based materials. When corrosive media such as moisture, oxygen, and chloride ions in the environment penetrate through the pores of the GRC material to the surface of the steel reinforcement, they destroy the passivation film on the steel surface, triggering electrochemical reactions. The corrosion products (such as iron hydroxide) expand to 2-4 times the volume of the original metal, and this expansion stress continuously acts on the surrounding cement matrix. When the stress exceeds the tensile strength of the GRC material (typically 3-5MPa), cracks appear on the component surface. Early cracks mostly appear as fine fissures along the direction of the steel reinforcement; as corrosion intensifies, the cracks gradually expand and connect, ultimately reducing the component's load-bearing capacity.

II. Multiple Impacts of Corrosion-Induced Cracking on GRC Components

Cracking of GRC components caused by steel reinforcement corrosion produces negative impacts across three dimensions: structural safety, durability, and economy. At the structural level, cracks weaken the bond between the steel reinforcement and the cement matrix, reducing the component's flexural and shear performance; in severe cases, this may cause anchorage failure or component detachment—for example, in a commercial complex project, failure to address corrosion cracks in time led to local deformation of the GRC exterior wall panels. In terms of durability, cracks accelerate the penetration of corrosive media, forming a vicious cycle of "corrosion–cracking–more severe corrosion" that shortens the component's service life by more than 30%. Economic losses are reflected in increased repair costs; according to industry statistics, the cost of repairing corroded GRC components accounts for approximately 20%-40% of the original construction cost, and the repair process may disrupt the building's normal use.

III. Qinglong's Corrosion Prevention and Control System and Technical Advantages for GRC Components

To address steel reinforcement corrosion, Qinglong Group, leveraging the technical strength of its national-level R&D center, has built a full-process prevention and control system. At the material level, a highly impermeable cement matrix combined with corrosion inhibitors keeps the chloride ion penetration coefficient of the GRC material below 1.0×10⁻¹²m/s. For steel reinforcement treatment, a dual protection of hot-dip galvanizing (zinc layer thickness ≥85μm) and epoxy coating is applied to enhance corrosion resistance. During production, BIM technology optimizes the rebar layout to ensure uniform protective layer thickness (≥25mm), and steam curing is used to improve matrix density. In addition, Qinglong has established a full-chain quality traceability system covering detailed design, construction and installation, and after-sales maintenance—for instance, in a landmark project, RFID chips were embedded to enable real-time monitoring of corrosion risks in GRC components.

IV. Industry Experience Sharing: Prevention and Treatment of Corrosion-Induced Cracking

Drawing on 28 years of engineering practice, Qinglong recommends preventing corrosion-induced cracking from three aspects: design, material selection, and construction. During the design phase, steel reinforcement should be kept from direct exposure to high-humidity environments, with UHPC composite layers used for enhanced protection where necessary. For material selection, priority should be given to products certified under the Technical Standard for Building Applications of Glass Fibre Reinforced Cement (GRC) (JGJ/T423-2018). During construction, curing humidity should be strictly controlled (≤60%) and sealant jointing properly performed. For components that have already developed corrosion cracks, Qinglong's patented repair technology can be applied: surface sealing + epoxy grouting + carbon fiber fabric reinforcement—a process that successfully restored the structural performance of GRC decorative components in a museum renovation project.

As a participant in the formulation of GRC industry standards, Qinglong Group has always been guided by its mission of "Creating Beautiful Architecture," minimizing the risk of steel reinforcement corrosion through technological innovation and strict quality control. Choosing Qinglong GRC means not only choosing quality products, but also a full-cycle solution covering early-stage consultation, detailed design, and lifetime maintenance, ensuring that every architectural work combines aesthetic value with structural safety.