What Are the Core Constituent Materials of GRC? What Are the Requirements for Alkali-Resistant Glass Fiber?

The performance advantages of GRC (Glass Fiber Reinforced Concrete) stem from scientific material proportions. The quality of the core constituent materials directly determines product strength, durability, and plasticity. Among them, alkali-resistant glass fiber serves as the reinforcement core, and its performance indicators are crucial to the overall quality of GRC, requiring strict compliance with industry standards and application specifications.

I. The Core Constituent Material System of GRC

The core constituents of GRC include cementitious materials, reinforcement materials, aggregates, admixtures, and water, with each component working synergistically to deliver stable performance. The cementitious materials are mainly Grade 42.5 or above white cement or ordinary Portland cement; Qinglong prioritizes high-grade white cement to ensure uniform surface color and a solid strength foundation. The reinforcement material is alkali-resistant glass fiber, which is key to improving the flexural and tensile performance of GRC. Aggregates use clean quartz sand with a particle size of 0.15-1.2mm and mud content ≤1%; Qinglong guarantees aggregate purity through multiple screening processes. Admixtures include water reducers, retarders, waterproofing agents, and more, which optimize construction performance and product durability. Water must be clean drinking water, with the water-cement ratio controlled between 0.35-0.45 to avoid cracking caused by excessive shrinkage.

II. Core Technical Requirements for Alkali-Resistant Glass Fiber

Alkali-resistant glass fiber must meet strict performance indicators to suit the long-term use requirements of GRC. First is alkali resistance: a zirconia-containing alkali-resistant formula must be adopted, and after 24 hours of immersion in alkaline solution at 100°C, the alkali resistance retention rate should be ≥75%. The imported alkali-resistant glass fiber selected by Qinglong achieves an alkali resistance retention rate of over 85%. Second is mechanical performance: the monofilament diameter must be between 13-24μm, the length 12-25mm, and the tensile strength ≥1000MPa, ensuring improved overall load-bearing capacity of GRC. Fiber dispersibility must be good, with no agglomeration; Qinglong uses specialized dispersion processes and mixing equipment to ensure fibers are evenly distributed in the concrete matrix. In addition, the bond between fiber and cement matrix must meet standards, with interface bond strength ≥3.5MPa, to prevent delamination during use.

III. Practical Points for Material Proportioning and Fiber Adaptation

The proportioning of core materials requires precise calculation. Qinglong optimizes formulations through orthogonal tests. The dosage of alkali-resistant glass fiber is typically 2%-5% of the cementitious material mass; too low a dosage cannot provide effective reinforcement, while too high a dosage can easily lead to fiber agglomeration. Material proportions need to be adjusted for different application scenarios. For example, for the 15mm-thick GRC carved panels of the Wuhan Hanxiu Theater, Qinglong optimized the fiber arrangement to improve the impact resistance of thin-walled components. For the project in the high salt-fog environment of Hainan, highly alkali-resistant fibers combined with anti-corrosion admixtures were selected to extend product service life. During production, mixing time and speed must be strictly controlled to ensure uniform fiber dispersion and avoid localized stress concentration.

IV. Qinglong's Material Quality Control System

Qinglong has established a full-process material quality control mechanism. All core materials come from well-known suppliers, and the alkali-resistant glass fiber is sourced from top international brands. Every incoming batch must pass testing of indicators such as alkali resistance and tensile strength. A provincial-level R&D center has been established to customize material formulations for different project needs. For example, for the GRC components of the Shanghai Qingpu R&D project, a balance between environmental friendliness and strength was achieved by optimizing the ratio of fiber to cementitious materials. Drawing on 28 years of industry experience, Qinglong has built a comprehensive material application database, ensuring that core material combinations adapt to various complex working conditions and laying a solid foundation for the quality of GRC products.