What Are the Raw Materials of GRC? An Analysis of Materials Science and the Quality Foundation of Qinglong Group

The performance of GRC (Glass Fiber Reinforced Cement) fundamentally depends on its raw material system. Premium GRC is a high-performance material composed of five major categories of raw materials—cementitious materials, reinforcing fibers, aggregates, admixtures, and functional additives—combined through scientific proportioning and precision craftsmanship. As an industry expert with 28 years of deep expertise in the GRC field, Qinglong Group holds exacting standards for every raw material: the core cementitious material is Grade 52.5 or higher Portland cement with strictly controlled alkali content (≤0.6%); reinforcing fibers are high-zirconia alkali-resistant glass fibers (ZrO₂ content ≥16%) to ensure long-term alkali resistance; aggregates are well-graded quartz sand with a maximum particle size usually not exceeding 1.2mm; admixtures include high-range water reducers, retarders, and more, used to adjust workability; in addition, active mineral admixtures such as silica fume and fly ash are often incorporated to improve the microstructure. In the red curtain wall project of the Wuhan Han Show Theatre, we achieved long-term stability of a high-saturation red color through our exclusively developed multi-component cementitious material system—after 8 years of wind and rain, the color remains as vivid as new. Raw materials are the wellspring of GRC's outstanding performance and admit no compromise whatsoever.

Cementitious Materials Are the Framework of the System

Cement is the binding core of GRC, and its type and quality directly determine strength development and long-term durability. Qinglong Group prefers low-alkali sulfoaluminate cement or ordinary Portland cement blended with substantial mineral admixtures, creating an alkaline environment friendly to glass fibers. At the same time, silica fume accounting for 20-30% of the total cementitious material is added; its extremely fine particles effectively fill capillary pores, greatly enhancing density and strength.

Reinforcing Fibers Are the Soul of Toughness

Alkali-resistant glass fiber is what distinguishes GRC from ordinary cement products. Like rebar in concrete, it provides crucial tensile strength and toughness. Fiber length (typically 12-20mm), diameter, surface treatment process, and volume dosage (typically 3-5%) all require precise design. Qinglong Group employs a fiber blending technique that distributes fibers randomly in three-dimensional space, forming an efficient load-transfer network.

Aggregates and Admixtures Optimize Performance

Aggregates serve as the skeleton and filler, and their grading directly affects the density and water demand of the mix. We use rigorously washed and graded quartz sand to ensure optimal particle shape and size distribution. High-range water reducers give the mix good fluidity even at extremely low water-binder ratios (typically 0.3-0.35), which is the process foundation for achieving high strength and high durability.

Functional Additives Deliver Specific Value

Depending on project requirements, toughening agents, waterproofing agents, early-strength agents, colorants, and more may be added. For example, to adapt to the severe cold climates of northern regions, we incorporate air-entraining agents to improve frost resistance; for colored GRC, inorganic mineral pigments are used to ensure lasting color.

Qinglong Group has established strict supplier management and incoming raw material inspection systems, ensuring stable quality for every batch of products at the source. We understand deeply that outstanding GRC stems from a profound understanding and precise control of every raw material.