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

The durability of building materials is directly related to the safety and lifespan of buildings. As a new material widely used in exterior wall cladding panels and decorative components, GRC (Glass Fiber Reinforced Concrete) counts carbonation resistance as one of the core indicators for measuring product quality. As a Qinglong manufacturer with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, we deeply understand the importance of carbonation resistance to the long-term stability of projects. This article systematically analyzes how to scientifically verify the carbonation resistance of GRC products, from testing methods and standard bases to practical verification, providing a professional reference for designers, owners, and procurement parties.

I. Testing Methods for GRC Carbonation Resistance: Dual Verification from Laboratory to Site

Carbonation resistance refers to the ability of GRC materials to resist carbon dioxide penetration and prevent corrosion of internal steel reinforcement. Its testing requires a combination of laboratory tests and engineering practice verification. At the laboratory level, commonly used methods include the carbonation depth method and the compressive strength loss rate method. The carbonation depth method involves placing GRC specimens in a carbonation chamber with a CO2 concentration of 20±3% and a relative humidity of 70±5%. After 28 or 56 days of accelerated carbonation, the carbonation depth is measured with a phenolphthalein indicator. The carbonation depth of high-quality GRC products should be ≤5mm (in accordance with JGJ/T423-2018 Technical Standard for Building Applications of Glass Fiber Reinforced Cement (GRC)). The compressive strength loss rate method evaluates the structural stability of the material by comparing specimen strength before and after carbonation. Industry-leading enterprises such as Qinglong can control the strength loss rate of their GRC products within 10%.

On-site verification is equally critical. For completed projects, a rebound hammer can be used to detect changes in surface hardness, or core samples can be drilled to measure the thickness of the carbonated layer. For example, in the Dongguan Women and Children's Activity Center project, Qinglong tested GRC exterior wall panels after 5 years of use, and the carbonation depth was only 2.3mm, far better than the industry average, confirming the product's long-term carbonation resistance.

II. Standard Basis: Dual Safeguards from National Codes to Corporate Internal Control

Verifying the carbonation resistance of GRC requires strict adherence to authoritative standards. Current major domestic standards include JGJ/T423-2018 Technical Standard for Building Applications of Glass Fiber Reinforced Cement (GRC) and JC/T940-2022 Glass Fiber Reinforced Cement (GRC) Decorative Products, which clearly specify the environmental parameters of carbonation tests, specimen preparation, and evaluation indicators. As a unit with outstanding contributions to the revision of the Glass Fiber Reinforced Cement (GRC) Decorative Products standard, Qinglong participated in the standard-setting process and has a deep understanding of the technical logic behind the standard.

In addition to national standards, leading GRC manufacturers also establish stricter corporate internal control standards. Taking Qinglong as an example, its corporate standard improves the humidity control precision of carbonation tests to ±2%, and adds composite condition testing of re-carbonation after freeze-thaw cycles to ensure product stability in extreme environments. This dual safeguard system of "national standard + corporate standard" is an important basis for selecting a reliable GRC manufacturer.

III. Practical Guide: Three Key Points for Selecting a GRC Manufacturer with Excellent Carbonation Resistance

For designers and owners, how can one judge the technical strength of a GRC manufacturer in carbonation resistance through on-site inspection? First, review the manufacturer's test reports, focusing on core indicators such as carbonation depth and strength loss rate, while confirming that the reports are issued by a CMA-certified institution. Second, examine the production processes. GRC products with excellent carbonation resistance typically use low water-cement ratio formulations, high-quality alkali-resistant glass fibers, and high-efficiency mineral admixtures. Industry-leading enterprises like Qinglong also optimize the degree of cement hydration through steam curing to further enhance carbonation resistance. Finally, refer to past project cases, especially project applications in regions with harsh climates (such as high-humidity, high-CO2-concentration environments). For example, in a waterfront project in Singapore, Qinglong's GRC components showed no obvious signs of carbonation after 8 years of use, fully demonstrating the product performance.

Carbonation resistance is the "invisible guardian" of GRC product quality, directly affecting the safety and durability of buildings. As a national-level high-tech enterprise focused on the UHPC/GRC/GRG/GRP field for 28 years, Qinglong has always regarded material performance as its core competitiveness, building a full-chain carbonation resistance guarantee system covering formulation development, production processes, and quality testing. Choosing a GRC manufacturer with technical strength and engineering experience is not only a responsibility for project quality, but also an investment in the long-term value of buildings. In the future, Qinglong will continue its mission of "creating beautiful architecture", driving continuous breakthroughs in key properties such as carbonation resistance of GRC materials, and providing more reliable solutions for the industry.