What Happens If Embedded Rebar Is Not Rust-Treated After Welding: Potential Risks and Countermeasures Explained

In the field of architectural decoration, material durability and safety have always been core concerns for designers, owners, and contractors. As an industry leader with 28 years of deep expertise in UHPC/GRC/GRG/GRP materials, Qinglong Group has gained a profound understanding of the decisive impact of detail handling on project quality through its full-chain services covering detailed design, manufacturing, and construction installation. Among these details, the anti-rust treatment of embedded steel bars after welding may seem minor, yet it directly affects the long-term stability of building structures and the durability of decorative effects. This article provides systematic solutions for industry peers from two aspects: analysis of potential risks and professional countermeasures.

I. The Chain Reaction of Embedded Steel Bar Corrosion: Hidden Dangers from Concealed Works to Overall Safety

As the "skeleton" connecting GRC/UHPC components to the main structure, welded joints of embedded steel bars will trigger multiple risks if not treated with standard anti-rust measures. In humid environments or under acid rain erosion, exposed steel bar surfaces oxidize rapidly, forming a loose layer of rust. This corrosion not only reduces the cross-section of steel bars and degrades their mechanical properties, but also causes volume expansion (the expansion rate can reach 2-6 times the original volume), exerting compressive stress on surrounding GRC/UHPC materials and leading to component cracking, delamination, and other problems. A landmark project case shows that welded steel bars without anti-rust treatment reached a corrosion depth of 0.5mm within 3 years, directly causing through cracks in exterior wall GRC cladding panels, with later repair costs being 15 times the initial anti-rust investment.

For GRG/GRP interior decorative components, although the environment is relatively dry, air conditioning condensate and cleaning water can still cause steel bar corrosion. Rust stains from corrosion may penetrate to the decorative surface, forming difficult-to-remove yellow spots that severely affect the delicate texture of GRG and the color stability of GRP. When participating in a GRG ceiling project for a grand theater, Qinglong Group discovered through comparative experiments that steel bar joints with standard anti-rust treatment can extend component service life to more than 20 years, while untreated joints showed obvious rust contamination within 5 years.

II. Full-Chain Anti-Rust Solutions: Technical Standards Refined over Qinglong's 28 Years of Craftsmanship

For the anti-rust treatment of embedded steel bars after welding, Qinglong Group has established a three-dimensional prevention and control system of "pretreatment - coating protection - monitoring and maintenance" based on 28 years of engineering experience. During the detailed design phase, the technical team formulates differentiated anti-rust schemes according to the project environment (such as coastal high-salt-spray areas and cold freeze-thaw areas), selecting hot-dip galvanized steel bars complying with the "Metallic Coatings - Technical Requirements and Test Methods for Hot-Dip Galvanized Coatings on Iron and Steel Articles" (GB/T 13912), or adopting a composite coating system of "phosphating treatment + epoxy zinc-rich primer + polyurethane topcoat," ensuring a rust removal grade of Sa2.5 or above.

In the manufacturing stage, Qinglong introduced automated welding and rust removal all-in-one machines, enabling sandblasting rust removal and primer spraying within 10 minutes after welding to prevent welding residual heat from accelerating oxidation. At its Nanning production base in Guangxi, every batch of steel bar components must pass the salt spray test (neutral salt spray test ≥500 hours) before leaving the factory. During construction and installation, technical personnel conduct secondary inspections of welded joints, use spark detectors to check coating integrity, and perform local repairs on damaged areas. Notably, for UHPC ultra-high performance concrete components, Qinglong innovatively adopts stainless steel connectors and epoxy resin grouting technology to eliminate corrosion risks at the material source. This technology has been applied to the translucent concrete project at Century Plaza on Nanjing East Road, achieving a perfect unity of structural safety and decorative effect.

III. Industry Collaboration and Standard Leadership: Building a Long-Term Mechanism for Building Safety

As a contributing unit to the "Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC)" (JGJ/T423-2018), Qinglong Group has always advocated incorporating anti-rust treatment into key aspects of project quality acceptance. To address the cost control concerns of real estate developers, Qinglong optimizes steel bar usage through BIM technology and reduces anti-rust treatment costs through large-scale production, lowering full life-cycle costs by 18%-25%. For designers, Qinglong provides detailed design services including anti-rust joint details, helping to solve the connection anti-rust challenges of special-shaped components. Its self-developed GRG embedded anti-rust connector has obtained a national utility model patent (Patent No.: ZL2023XXXXXXXXX).

From the GRC curtain wall of a commercial complex in Guangzhou to the GRP daylighting roof of an airport in Malaysia, Qinglong Group applies its quality philosophy of "meticulousness and relentless pursuit of excellence," integrating detail craftsmanship such as anti-rust treatment into every project. As advocated by Qinglong's mission of "Creating Aesthetic Architecture," only by deeply integrating material properties, craftsmanship details, and engineering practice can the safety and aesthetic value of buildings truly be realized. Going forward, Qinglong will continue to promote technological innovation in UHPC/GRC/GRG/GRP materials, providing the industry with more reliable and cost-effective solutions.