When Is the Best Time to Demold GRC Components? Key Influencing Factors and a Practical Guide

Precisely grasping the demolding timing of GRC components is the golden node that determines product quality and production efficiency. 28 years of industry experience tells you: scientific judgment is more reliable than empiricism.

In the field of architectural decorative materials, GRC (Glass Fiber Reinforced Concrete) is widely used for exterior wall cladding panels and decorative components in high-end projects such as grand theaters, commercial complexes, and landmark buildings, thanks to its lightweight, high-strength, and richly formable characteristics. As a national high-tech enterprise integrating detailed design, manufacturing, and construction installation, Qinglong Group has accumulated systematic experience in GRC component production, particularly developing a scientific methodology for controlling demolding timing. This article analyzes the core logic of GRC component demolding, from technical principles and influencing factors to practical key points.

The Technical Essence of GRC Component Demolding Timing: Balancing Strength and Structural Stability

Demolding GRC components is not simply a matter of a time point, but a comprehensive reflection of the material's hydration reaction and structural load-bearing capacity. The demolding process can only begin when the ettringite and C-S-H gel generated by the hydration of cement-based materials reach more than 70% of the design strength, and the surface hardness of the components meets the requirements for crack resistance and deformation resistance. Qinglong Group's laboratory data shows that ordinary GRC components can reach demolding strength within 24-48 hours under standard curing conditions, while complex shaped components require extension to 72 hours; this parameter needs to be dynamically adjusted based on the material mix ratio and ambient temperature and humidity.

Three Core Influencing Factors: Full-Dimensional Control from Materials to Environment

Material mix ratio is the fundamental variable. Qinglong uses customized fiber content (usually 4-6% by volume) and specialized admixtures in production, precisely controlling the hydration rate by adjusting the water-cement ratio and retarder dosage. For example, in high-temperature seasons, the proportion of water-retaining agents is appropriately increased to prevent early cracking caused by rapid evaporation of surface moisture. Environmental temperature and humidity are key regulating factors; the ideal curing environment should maintain a temperature of 20±3℃ and a relative humidity of ≥90%. The constant temperature and humidity curing workshop at the production base in Nanning, Guangxi keeps the demolding success rate stable at over 99.5%.

Component shape and size are equally important. For large GRC relief panels with a thickness exceeding 150mm, Qinglong adopts a “segmented demolding” process: first removing the non-load-bearing side molds, then removing the load-bearing main molds after internal stress is released; for hyperbolic components with a curvature radius of ≤300mm, shrinkage allowance must be reserved at the mold design stage, combined with the use of elastic release agents, to avoid structural damage caused by forced demolding.

Four-Step Practical Guide: Qinglong's Standardized Process from 28 Years of Experience

Step 1: Strength testing. Use a rebound hammer to measure surface hardness, and at the same time make test blocks cured under the same conditions for compressive strength testing, confirming that both indicators meet the standards. Step 2: Appearance inspection. Focus on checking whether there are micro-cracks at component edges and whether embedded parts are secure; defects such as honeycombing and pitted surfaces must be repaired before demolding. Step 3: Demolding sequence planning. Follow the principle of “non-load-bearing before load-bearing, side molds before bottom molds”; large components require specialized lifting equipment to ensure even force distribution. Step 4: Post-demolding curing transition. Immediately transfer to a secondary curing kiln for 7 days of steam curing, allowing the strength to continue rising to 100% of the design value.

As an enterprise that participated in formulating the “Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC),” Qinglong Group has always emphasized refined management of the demolding process. From the special-shaped GRC curtain wall at the Dongguan Women and Children's Activity Center to the translucent concrete project at Century Plaza on Nanjing East Road, it is the strict control of every production stage that has earned an excellent reputation for engineering quality. For designers and project owners, choosing a GRC manufacturer with full-chain service capabilities not only provides technical support, but also ensures project delivery efficiency and quality stability through standardized production processes.