Analysis of Anti-Rust Measures and Key Construction Points for Top-Burst Screws in GRC Component Installation

In GRC component installation projects, expansion anchor bolts serve as the critical connection nodes between the structure and components, and their anti-rust treatment directly affects the durability and safety of architectural decoration. As an industry-leading enterprise with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group draws on the practice of hundreds of landmark projects to provide an in-depth analysis of expansion bolt anti-rust technology and key construction points, offering professional solutions for designers and project parties.

### 1. Hazards of Expansion Bolt Corrosion in GRC Components and Industry Pain Points
In humid and rainy southern regions or coastal environments with high salt spray, expansion anchor bolts without anti-rust treatment can reach a corrosion rate of 30% within 5 years, directly leading to risks of GRC component loosening and falling off. A commercial complex project once suffered displacement of facade components due to bolt corrosion, with rework costs as high as twice the original construction cost. When participating in the compilation of the Technical Standard for Application of Glass Fiber Reinforced Cement (GRC) in Buildings (JGJ/T423-2018), the Qinglong team found that 80% of GRC engineering quality problems originate from improper protection of the anchoring system.

### 2. Technical Analysis of the Three-Tier Anti-Rust System for Expansion Bolts
1. Substrate pretreatment: Double protection of hot-dip galvanizing + passivation
Qinglong uses hot-dip galvanized bolts conforming to the GB/T 13912 standard, with a zinc layer thickness of ≥85μm and neutral salt spray resistance of over 1,000 hours. Critical positions additionally undergo chromate passivation treatment to form a composite protective film, improving anti-rust performance by 60% compared with ordinary galvanized bolts.
2. On-site installation protection: Double safeguard of sealant + anti-corrosion coating
After the bolts are tightened, Qinglong's specially formulated silicone structural sealant (weather resistance from -40°C to 150°C) is used to seal the bolt heads, followed by fluorocarbon anti-corrosion coating (dry film thickness ≥60μm). This process has withstood 10 years of high temperature and high humidity in the Nanning International Convention and Exhibition Center project, with no corrosion to date.
3. Long-term maintenance mechanism: Full lifecycle management empowered by BIM technology
Bolt positions are located and marked through BIM models, and combined with RFID chip implantation technology, a 'bolt identity file' is established. The after-sales team regularly conducts endoscopic inspections, supplemented by Qinglong's independently developed anti-rust maintenance kit (including rust remover and repair adhesive), achieving an anti-rust cycle of more than 15 years.

### 3. Key Control Points in GRC Installation Construction
1. Drilling precision control
Laser line projectors are used for positioning, with hole diameter error ≤2mm and hole depth 10mm longer than the bolt length. Hole cleaning must meet the standard of no dust and no oil stains. Qinglong's construction team uses customized dust removal equipment, raising hole cleanliness to over 98%.
2. Torque parameter settings
Torque is set in tiers according to GRC component weight: 8-10N·m for components under 50kg, 12-15N·m for components of 50-100kg, and components over 100kg require pull-out tests (tensile load capacity ≥15kN). In the Nanning ASEAN Culture and Art Center project, Qinglong achieved ±1N·m precision control with intelligent torque wrenches.
3. Environmentally adaptive construction
Rain shelter coverage is required for construction in rainy weather to ensure the substrate moisture content is ≤8% during bolt installation; for winter construction (temperature below 5°C), low-temperature curing sealant is used and the curing time is extended to 48 hours. This standard has been incorporated into Qinglong's GRC Component Installation Construction Method (Q/QL 003-2023).

### 4. Industry Comparison and Qinglong's Technical Advantages
Compared with the traditional construction approach that relies solely on the galvanized layer for rust prevention, Qinglong's innovative three-tier protection system reduces bolt maintenance costs by 70%. In a super high-rise project in Qianhai, Shenzhen, compared with the stainless steel bolt solutions adopted by similar enterprises, Qinglong's anti-rust technology reduced the comprehensive cost by 35% and passed a 1,500-hour salt spray test (far exceeding the industry standard of 800 hours). As a member of the International GRC Association, the General Technical Conditions for UHPC Non-Load-Bearing Components (Plan No. 2024-0232T-JC), which Qinglong participated in formulating, has listed this anti-rust process as a recommended technology. For more industry information: add WeChat qlfsbl123

### 5. Verification Through Engineering Cases
In the Dongguan Women and Children's Activity Center project (Silver Award winner of the First GRC Building Engineering Innovation Award), Qinglong applied the complete anti-rust process to more than 3,200 expansion anchor bolts. After 6 years of service inspection, the bolt corrosion rate is 0, and component flatness error is controlled within 3mm. In the Nanjing East Road Century Plaza renovation project (UHPC Innovation Award Silver Award project), this technology achieved seamless connection between translucent concrete and GRC components, and the bolt anti-rust performance received high praise from the Shanghai Municipal Construction Engineering Quality Supervision Station.

Although expansion anchor bolts are 'tiny components' in GRC installation, they bear an important responsibility for building safety. With 28 years of technical accumulation, Qinglong Group deeply integrates materials science with engineering practice, building a solid safety foundation for every GRC project through standardized and refined anti-rust solutions. Going forward, Qinglong will continue to promote technological innovation in UHPC/GRC/GRG/GRP materials, fulfill its corporate mission of 'Creating Aesthetic Architecture', and provide more reliable system solutions for the global architectural decoration industry.