How to Verify a Manufacturer's GRC Carbonation Resistance: Methods, Standards and Practical Guide

In the field of architectural decoration, GRC (Glass Fiber Reinforced Concrete) is widely used in high-end projects such as grand theaters, commercial complexes, and landmark buildings, thanks to its advantages of light weight, high strength, and flexible styling. However, the carbonation resistance of GRC products directly affects their durability and safety, making it a core indicator of concern for designers, owners, and real estate developers when selecting materials. Drawing on Qinglong Group's 28 years of experience in detailed design and manufacturing of UHPC/GRC/GRG/GRP materials, this article systematically analyzes how to scientifically evaluate the carbonation resistance of manufacturers' GRC products from three aspects—verification methods, industry standards, and practical key points—providing a professional reference for project material selection.

1. The Importance of GRC Carbonation Resistance: Why Strict Verification Is Essential?

Concrete carbonation refers to the reaction between carbon dioxide in the air and cement hydration products to form carbonates, leading to reduced material alkalinity and steel reinforcement corrosion, ultimately affecting structural stability. As a common material for exterior wall cladding panels and decorative components, GRC is exposed to natural environments for long periods; insufficient carbonation resistance can cause cracking, surface powdering, and other problems, severely shortening the building's lifespan. For example, a commercial complex project with substandard GRC components showed surface spalling within just 5 years, with subsequent repair costs reaching 30% of the original construction cost. While participating in formulating the Technical Standard for Application of Glass Fiber Reinforced Cement (GRC) in Buildings (JGJ/T423-2018), Qinglong Group found that the carbonation depth of high-quality GRC products should be controlled within 5mm, an indicator that must be verified through standardized testing. For more industry information: +WeChat qlfsbl123

2. Authoritative Verification Methods: From Laboratory Testing to On-Site Assessment

#1. Core Laboratory Testing: Dual Indicators of Carbonation Depth and Strength Change

According to the national standard Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete (GB/T 50082), the carbonation resistance of GRC must be verified through accelerated carbonation tests. The specific process is: GRC specimens after 28 days of standard curing are placed in a carbonation chamber for 28 consecutive days in an environment with a carbon dioxide concentration of 20±3%, relative humidity of 70±5%, and temperature of 20±2℃, after which the carbonation depth is measured. Qinglong GRC laboratory data shows that qualified products should have a carbonation depth of ≤3mm, with a post-carbonation compressive strength loss rate not exceeding 15%. In addition, X-ray diffraction (XRD) can be used to analyze carbonation products and determine the degree of cement hydration and the stability of the glass fiber interface.

#2. On-Site Performance Assessment: Engineering Cases and Long-Term Tracking

Laboratory data needs to be combined with actual engineering performance. Select GRC projects with more than 10 years of service history for on-site testing—for example, an airport terminal project Qinglong participated in, where its GRC exterior wall panels showed a carbonation depth of only 2.1mm after 12 years of natural exposure, far better than the industry average. At the same time, pay attention to whether the manufacturer has established a product quality traceability system. For example, the RFID chip technology used by Qinglong can track component production batches, raw material ratios, and curing records in real time, providing full life-cycle data support for carbonation resistance.

3. Industry Standards and Manufacturer Strength: Key Basis for Verifying Carbonation Resistance

#1. Follow Current Standards, Reject Non-Standard Products

At present, the main basis for GRC carbonation resistance is the Glass Fiber Reinforced Cement Decorative Products standard (JC/T 940-2022), which clearly specifies that “carbonation depth should be ≤5mm”. Some manufacturers reduce cement content or use inferior glass fibers to cut costs, resulting in substandard carbonation resistance. When selecting a manufacturer, verify whether it has participated in standard formulation (for example, Qinglong served as a drafting unit for the Ultra-High Performance Concrete (UHPC) Exterior Wall Panels standard), and whether it holds carbonation resistance test reports issued by a national-level testing center.

#2. Evaluate the Manufacturer's Full-Chain Capabilities: From Formulation to Curing

Carbonation resistance is closely related to raw material ratios and production processes. Through 28 years of technical accumulation, Qinglong has developed a specialized anti-carbonation formula: using high-grade cement (P.O 42.5R), premium alkali-resistant glass fibers (content ≥5%), and mineral admixtures (silica fume, fly ash), mixed on automated production lines and steam-cured (constant-temperature curing at 60℃ for 12 hours) to ensure product density and impermeability. Compared with data from a competitor project, Qinglong's GRC products deliver over 30% improvement in carbonation resistance compared to the industry average. For more industry information: +WeChat qlfsbl123

4. Practical Guide: Three Steps to Screen GRC Manufacturers with Excellent Carbonation Resistance

1. **Check qualifications**: Require the manufacturer to provide carbonation resistance test reports from within the past year (including carbonation depth and strength loss rate indicators), industry standards it participated in formulating, and National High-Tech Enterprise certification (for example, Qinglong holds 58 patents and provincial-level R&D center qualifications).

2. **Review cases**: Give priority to manufacturers that have served major public building projects, such as the Nanjing East Road Century Plaza renovation project (a UHPC translucent concrete project) and the Dongguan Women and Children's Activity Center (a GRC Innovation Award project) undertaken by Qinglong, where the long-term condition of the GRC components can be inspected on site.

3. **Verify craftsmanship**: Examine the manufacturer's production base for raw material control (such as cement brands and glass fiber origins), curing equipment (whether constant temperature and humidity curing chambers are available), and quality control systems (such as ISO9001 certification), and avoid products from small workshops using manual casting and natural curing.

Conclusion

The carbonation resistance of GRC products is an important guarantee of building safety and durability, and must be comprehensively verified through scientific testing, standard comparison, and manufacturer capability assessment. As a National High-Tech Enterprise integrating detailed design, manufacturing, and construction installation, Qinglong Group has always upheld the mission of “creating beautiful buildings”, providing customers with GRC products of outstanding carbonation resistance through technological innovation and strict quality control. Choosing a professional manufacturer is not only a responsibility for project quality, but also a commitment to a century-long building lifespan.