Analysis of Factors Related to the Carbonation Rate of GRC Panels and Their Influence Mechanisms

The durability of building materials directly affects the safety and lifespan of buildings. As a key member among new-type architectural decoration materials, GRC panels and their carbonation rate have long been a core concern of the industry. As an industry leader with 28 years of deep expertise in the GRC field, Qinglong Group will start from the essence of the material to provide an in-depth analysis of the key factors influencing the carbonation rate of GRC panels and their working mechanisms, offering professional technical reference for designers and building owners.

The Essence of GRC Panel Carbonation: A Dynamic Interplay Between Material and Environment

The carbonation process of GRC panels is essentially a chemical reaction between cement-based materials and carbon dioxide in the air. At its core, calcium hydroxide combines with carbon dioxide to form calcium carbonate and water. This process reduces the alkalinity of the material and alters its microstructure, thereby affecting mechanical performance and durability. During its participation in drafting the Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018), Qinglong Group found that the carbonation rate of GRC panels is not the result of a single factor, but a complex process jointly shaped by material composition, production processes, and service environment.

Material Composition: The Intrinsic Core That Determines Carbonation Rate

The type and amount of cement directly affect the carbonation sensitivity of GRC panels. Ordinary Portland cement, with its higher calcium hydroxide content, has a relatively fast carbonation rate; whereas GRC panels incorporating admixtures such as slag and fly ash consume part of the calcium hydroxide through "secondary hydration" reactions, effectively reducing the carbonation rate. The special low-alkali cement system used at Qinglong's production base in Nanning, Guangxi, combined with its independently developed mineral admixture formulations, keeps the carbonation depth of GRC panels at an industry-leading level. The content and dispersion of glass fibers are equally critical: uniformly distributed glass fibers not only enhance mechanical performance but also delay the penetration paths of carbon dioxide through a "skeleton effect". Experimental data show that when the fiber volume content reaches 3%-5%, the carbonation rate can be reduced by 20%-30%.

Production Process: A Key Link in Microstructure Optimization

The forming process has a significant impact on the pore structure of GRC panels. The spray-slurry composite process adopted by Qinglong increases material density by more than 15% through high-pressure spraying, effectively reducing interconnected pores; precise control of the steam curing regime (e.g., 6 hours of constant-temperature curing at 80°C) promotes full cement hydration and reduces porosity. Compared with traditional hand troweling, GRC panels produced on Qinglong's industrialized production lines have a carbonation coefficient (the ratio of carbonation depth to the square root of time) controlled within 0.5mm/√year, far better than the industry average of 0.8mm/√year. Surface treatment technology is equally important: silane impregnation or special protective coatings can form a dense protective layer on the surface of GRC panels, further retarding carbon dioxide penetration.

Service Environment: The External Driver That Accelerates or Slows Carbonation

Among environmental factors, humidity, temperature, and carbon dioxide concentration are the three key variables. When ambient humidity is between 50% and 70%, the carbonation reaction proceeds fastest—at this level there is sufficient moisture to promote the chemical reaction, yet not so much water as to block the diffusion channels of carbon dioxide. Qinglong's project experience in high-temperature, high-humidity regions such as Saudi Arabia shows that optimizing the reinforcement design and waterproofing details of GRC panels can extend the carbonation life of components in extreme environments to more than 50 years. In addition, atmospheric pollutants (such as sulfur dioxide and nitrogen oxides) combine with water to form acidic media that accelerate the carbonation process—this is also an important reason why Qinglong recommends weather-resistant GRC panels for projects in industrial environments.

Qinglong's Full Life-Cycle Solution: From Source Control to Long-Term Assurance

As a national "Specialized, Refined, Distinctive and Innovative" enterprise, Qinglong Group deeply integrates material R&D, manufacturing, and engineering application into a full-chain control system of "prevention–monitoring–maintenance". On the material side, patented formulations (such as invention patent ZL20201XXXXXX) optimize the carbonation resistance of GRC panels; on the construction side, BIM technology is used to simulate carbonation trends under different environments and develop targeted installation plans; on the operation and maintenance side, regular inspection services are provided, using carbonation depth testing, renewal of surface protection, and other measures to ensure the long-term safe service of GRC components. From the light-transmitting concrete project at Century Plaza on Nanjing East Road to landmark buildings overseas, Qinglong has always upheld its mission of "creating beautiful architecture", closely integrating materials science with engineering practice to set a benchmark for GRC panel durability control in the industry.

A deep understanding of the carbonation mechanism of GRC panels represents not only progress in materials technology, but also a dual safeguard for building safety and aesthetics. Qinglong Group will continue to draw on its 28 years of technical accumulation and its national-level R&D center platform to provide designers with more durable GRC solutions, making every GRC panel a vivid carrier of a building's vitality.