What Are the Key Points of the High-Strength GRC Panel Production Process? Core Production Process Points and Quality Control Standards

High-strength GRC panels (flexural strength ≥15MPa, compressive strength ≥60MPa), with their excellent mechanical properties, are widely used in demanding applications such as load-bearing components and high wind-pressure exterior walls. The production process requires precise control of key stages including raw materials, molding, and curing to ensure performance meets standards. Drawing on years of experience in high-strength GRC production, Qinglong analyzes the core process essentials.

I. Key Points of Raw Material Selection and Mix Design

Raw materials and formulation are the foundation of high-strength GRC panel performance. Cement: high-grade, low-alkali sulphoaluminate cement with strength grade ≥42.5 is selected to ensure matrix strength; aggregates: high-purity quartz sand with a particle size of 0.15-1.2mm and reasonable grading to improve density and wear resistance; glass fibers: alkali-resistant chopped fibers, 12-24mm in length, at a dosage of 3.5%-4.5%, evenly dispersed to avoid agglomeration—Qinglong uses dedicated dispersion equipment to ensure consistent fiber distribution; admixture optimization: a high-range water reducer (dosage 0.8%-1.2%) is added to lower the water-binder ratio to 0.28-0.32, combined with silica fume (dosage 8%-10%) to enhance matrix density and strength.

II. Key Points for Precise Control of the Molding Process

The molding process directly determines the structural density and strength of high-strength GRC panels. High-pressure spray-up molding is adopted, with spray pressure controlled at 0.6-0.8MPa to ensure the slurry is fully compacted and porosity reduced below 2%; layered spray molding is applied with each layer 5-8mm thick and interlayer intervals controlled at 15-20 minutes to ensure strong interlayer bonding and prevent delamination cracking; high-precision steel molds are selected with surface flatness ≤0.3mm/m to ensure dimensional accuracy and surface quality of the panels. In the Shenzhen Pingshan High-Tech Zone Comprehensive Service Center project, Qinglong achieved a flexural strength of 18MPa for high-strength GRC panels through high-pressure spray-up molding.

III. Key Points of the Curing Process for Strength Assurance

Scientific curing ensures the full development of high-strength GRC panel strength. Moisture-retention curing begins immediately after initial setting to prevent surface cracking caused by water loss; during the standard curing stage, temperature is controlled at 20±2°C and relative humidity at ≥95%, with curing time of no less than 7 days to ensure full cement hydration; steam curing is optimized using a three-stage “temperature rise–constant temperature–temperature drop” process, with a heating rate ≤20°C/h, constant temperature of 50-60°C held for 4-6 hours, and cooling rate ≤15°C/h to prevent internal micro-cracking caused by thermal stress. Through steam curing, Qinglong enables high-strength GRC panels to reach 70% of design strength at 3 days and 90% at 7 days.

IV. Key Points of Quality Control and Testing in the Production Process

Full-process quality control ensures stable performance of high-strength GRC panels. Raw material testing: every batch of incoming raw materials is tested, with indicators such as cement strength and fiber alkali resistance required to meet standards; in-process testing: samples are taken during spraying to test the slurry water-binder ratio and fiber dosage, ensuring compliance with formulation requirements; finished product testing: each batch is sampled for compressive and flexural strength testing with a pass rate of 100%, and indicators such as surface flatness and dimensional accuracy are also tested; non-destructive testing: ultrasonic testing instruments are used to check internal density, preventing internal defects from affecting strength. Qinglong has established a dedicated quality control system for high-strength GRC panels to ensure stable and reliable product performance.