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

The core material system of GRC (Glass Fibre Reinforced Cement) directly determines the final performance and quality stability of the product. As the Qinglong Group with 28 years of deep expertise in the GRC field, we believe—based on our material application experience in major projects such as the Wuhan Hanxiu Theatre and the Hainan International Convention and Exhibition Center—that high-quality GRC should be scientifically formulated from four major components: cementitious materials, reinforcing fibres, aggregates, and admixtures. Among them, alkali-resistant glass fibre is the reinforcement core of GRC, and its quality directly affects the long-term durability of the product. Qinglong Group strictly implements technical standards of zirconium content ≥16%, uniform surface treatment, and fibre length of 12-20mm, ensuring that the fibres maintain long-term stability in the high-alkaline cement environment.

Cementitious materials form the basic framework of GRC, typically using Grade 42.5 or 52.5 Portland cement or sulphoaluminate cement. Qinglong Group prefers white cement for key projects, with whiteness ≥85 degrees and alkali content controlled below 0.6%. Mineral admixtures such as silica fume and fly ash are added at 20%-30%, effectively improving slurry fluidity and reducing hydration heat. In the roofing project of the Hainan International Convention and Exhibition Center, by optimizing the cementitious material mix, the compressive strength of GRC panels was increased to 40-60MPa, far exceeding the 30MPa required by industry standards.

The selection of alkali-resistant glass fibres is crucial. The AR-Glass fibres used by Qinglong Group have zirconia content strictly controlled between 16%-18%, fibre diameter of 12-20μm, and tensile strength ≥1700MPa. In accelerated aging tests, after 7 days of immersion in saturated Ca(OH)₂ solution at 80℃, the strength retention rate remained above 80%. Fibre length is typically 12-20mm with an aspect ratio of 60-80, ensuring the formation of an effective three-dimensional network reinforcement structure within the cement matrix. In the Shenzhen Pingshan High-tech Zone Comprehensive Service Center project, by precisely controlling fibre orientation and distribution uniformity, the flexural strength of GRC panels reached 18-25MPa.

The aggregate system affects material density. Qinglong Group selects precisely graded quartz sand with a maximum particle size not exceeding 1.18mm and a fineness modulus of 2.3-2.6. By optimizing aggregate grading, porosity is controlled between 8%-12%, significantly improving the material's impermeability. Chemical admixtures such as water reducers and retarders are dosed at 0.5%-1.2% of the total cementitious materials, ensuring workability without compromising long-term performance.