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

GRC's core constituent materials include cementitious materials, aggregates, alkali-resistant glass fibers, and admixtures. These four components work synergistically to form its lightweight, high-strength characteristics, among which alkali-resistant glass fibers are the key to crack resistance. Qinglong enforces strict selection standards for them to ensure long-term product stability.

I. Analysis of GRC's Core Constituent Materials

The core materials can be divided into four categories by function, and scientific proportioning is the guarantee of performance. Cementitious materials: mainly low-alkali sulfoaluminate cement or Portland cement, accounting for 25%-35%; Qinglong gives priority to low-alkali cement (alkali content ≤0.6%) to reduce the risk of alkali-aggregate reaction; Aggregates: high-purity quartz sand or river sand, particle size 0.15-0.6mm, accounting for 45%-55%; Qinglong uses washed quartz sand (mud content ≤0.3%) to ensure clean particles; Alkali-resistant glass fibers: accounting for 2%-3%, they are the "backbone" of GRC, improving flexural and crack resistance; Admixtures: accounting for 1%-2%, including high-efficiency water reducers, retarders, etc.; Qinglong's customized water reducer achieves a water reduction rate of over 30%, optimizing workability.

II. Core Technical Requirements for Alkali-Resistant Glass Fibers

The requirements for alkali-resistant glass fibers focus on strength, alkali resistance, and dispersibility, which directly affect GRC's service life. Mechanical properties: tensile strength ≥1500MPa, elongation at break ≥3%; the fibers selected by Qinglong generally reach a tensile strength of over 1800MPa, ensuring the reinforcing effect; Alkali resistance: after a 1000h alkali resistance test, the strength retention rate is ≥85%; Qinglong uses imported alkali-resistant glass fibers with a zirconium coating on the surface, offering excellent resistance to alkali corrosion; Morphological parameters: diameter 13-18μm, length 12-25mm, with the length-to-diameter ratio (L/D) controlled at 600-1000; Qinglong determined through experiments that 18mm-long fibers offer the best suitability and can be evenly dispersed in the matrix; Dispersibility: free of clumping and easy to mix with mortar; during production, Qinglong adopts mechanical dispersion plus manual assistance to ensure uniform fiber distribution and avoid localized strength weakness.

III. Material Selection Standards and Corporate Practice Cases

Strict material selection and practical verification ensure the fibers perform optimally. Material selection process: Qinglong has established a three-tier material selection standard—first reviewing supplier qualifications, then testing fiber performance, and finally verifying suitability through small-batch trial production; Project application: the 15mm-thick GRC carved panels at the Wuhan Hanxiu Theater used alkali-resistant fibers with a diameter of 16μm, achieving a flexural strength of 22MPa with no cracking after 10 years of use; Standards compliance: fully compliant with the "Technical Standard for Glass Fiber Reinforced Cement (GRC) Building Applications" (JGJ/T423-2018); when participating in drafting this standard, Qinglong included fiber performance indicators as one of the core clauses.