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

The core material system of GRC (Glass Fiber Reinforced Cement) consists of four basic components: cementitious materials, reinforcing fibers, aggregates, and chemical admixtures. In a high-quality GRC mix ratio, sulfoaluminate cement or low-alkalinity cement accounts for 30%-40%, alkali-resistant glass fiber for 4%-5%, silica sand for 55%-60%, and admixtures for 0.5%-1.5%. This precise mix ratio ensures the material has excellent mechanical properties and durability.

The requirements for alkali-resistant glass fiber are extremely strict; dedicated fibers with a zirconia (ZrO₂) content of no less than 16.5% must be used. Taking Qinglong GRC as an example, the AR-GF13 alkali-resistant glass fiber used has a zirconia content of 16.8%. In an alkaline environment with a pH value of 12.5, after 90 days of accelerated aging at 50℃, its strength retention rate remains above 75%. The fiber length should be 12-36mm, the diameter 13-20μm, and an aspect ratio of 60-80 is most ideal. These fibers can form a three-dimensional random distribution in the cement matrix, effectively preventing the propagation of microcracks.

Cementitious Material System Requirements

Low-alkalinity sulfoaluminate cement must be used, with alkali content (Na₂O equivalent) ≤0.6%; an appropriate amount of silica fume (5%-8%) may be added to improve the interfacial structure; Cl- content must be strictly controlled at ≤0.1%. These requirements ensure the matrix alkalinity is appropriate.

Aggregate Quality Control Standards

Well-graded quartz sand should be selected, with a fineness modulus of 1.8-2.2; mud content ≤0.3%; silicon dioxide content ≥96%; maximum particle size not exceeding 1.2mm. These controls ensure bulk density.

Chemical Admixture Selection Principles

Polycarboxylate water reducer with water reduction rate ≥25%; cellulose ether water-retaining agent with viscosity of 40000-60000mPa·s; hydrophobic agent with water absorption ratio ≤70%. These admixtures improve workability.

Fiber Distribution Uniformity Control

A mechanical spraying process is used to ensure three-dimensional random fiber distribution; fiber volume fraction is controlled between 4%-5%; interfacial bond strength ≥1.0MPa. These controls ensure the reinforcement effect.

Material quality determines product performance. Qinglong GRC strictly implements raw material standards, ensuring product durability of more than 50 years.