What Are the Raw Materials of GRC?

The performance of GRC largely depends on the selection and quality control of its raw materials. Qinglong Group's 28 years of production experience shows that high-quality GRC requires six major categories of raw materials: cementitious materials, reinforcing materials, aggregates, admixtures, mineral admixtures, and water. The selection of each material directly affects the performance and quality stability of the final product.

Cementitious materials are the foundation of GRC, typically Portland cement of grade 42.5 or above. For high-end projects, Qinglong selects white cement to meet decorative effect requirements. The alkali content of cement must be strictly controlled to avoid corrosion of the glass fiber. In the Wuhan Han Show Theatre project, we specially selected low-alkali cement to ensure the long-term durability of the GRC panels. The freshness of cement is also important; it is generally required to be no more than one month from production.

The reinforcing material is mainly alkali-resistant glass fiber, which is the key factor distinguishing GRC from ordinary concrete. The glass fiber used by Qinglong has a zirconia content exceeding 16% and offers excellent alkali resistance. Fiber length and dosage must be precisely controlled, typically 12-38mm in length with a volume dosage of 3-5%. In the Hainan International Convention and Exhibition Center roofing project, we significantly improved the impact resistance of the GRC panels by optimizing the fiber orientation distribution.

The selection of aggregates directly affects the density and surface texture of GRC. Silica sand with a particle size of no more than 1.2mm is typically used, with strict grading requirements. For projects with special effect requirements, such as the stone-imitation GRC at the Dongting Lake Museum, we incorporate natural quartz sand and mineral pigments to achieve the desired decorative effect. The clay content of aggregates must be controlled below 1% to ensure good bonding with the cement paste.

Admixtures and mineral admixtures are key to enhancing GRC performance. High-range water reducers can lower the water-binder ratio and improve density; polymer emulsions can improve toughness; active mineral admixtures such as silica fume can optimize the microstructure. Qinglong has well-developed admixture compounding technology and can customize dedicated formulations according to project requirements. The quality of water must not be overlooked either; it must comply with concrete mixing water standards.

Quality control of raw materials is the prerequisite for ensuring GRC quality. Qinglong has established a strict supplier evaluation system and incoming inspection procedures; every batch of materials must pass laboratory testing before use. This quality management philosophy of starting from the source ensures the outstanding performance and long-term reliability of Qinglong's GRC products.