How Many Days Is the Minimum Curing Period for GRC Components? Curing Cycles and Key Points Explained

In the field of architectural decoration, GRC components (Glass Fiber Reinforced Concrete), with their lightweight, high-strength nature and rich styling, are widely used in various projects such as grand theaters, commercial complexes, and landscape gardens. However, many project managers often neglect the curing stage after construction, resulting in problems such as component cracking and surface chalking. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP, Qinglong Group, drawing on the Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018) and more than a thousand engineering projects, provides a detailed explanation of the scientific curing cycle and key points for GRC components.

### I. The "Golden Standard" for GRC Component Curing Period: Why at Least 28 Days?

The curing of GRC components is essentially the hydration reaction process of cement-based materials, which must go through a complete cycle from initial setting and final setting to strength stabilization. According to Qinglong Group's laboratory data, under standard curing conditions at 20°C, GRC components reach 60% of their design strength at 7 days and over 95% at 28 days, at which point the internal structure of the material tends to stabilize, with crack resistance and durability significantly improved. If the curing period is shortened to 14 days, the risk of later-stage cracking will increase by 40%, which is the core reason why GRC Decorative Products (JC/T940-2022) explicitly stipulates that "the natural curing period shall not be less than 28 days." For special environments such as high temperatures and severe cold, the Qinglong technical team recommends extending it to 35 days and adopting measures such as covering for moisture retention or steam curing.

### II. Phased Curing Key Points: Full-Process Control from Production to Installation

**1. Production Stage Curing (Days 1-7): Laying the Foundation of Strength**
At Qinglong's Guangxi production base, GRC components enter a constant-temperature, constant-humidity curing room immediately after demolding, using the dual protection of spraying plus film wrapping to ensure ambient humidity ≥90% and temperature controlled at 15-25°C. At this stage, the focus is on monitoring whether micro-cracks appear on the component surface; once detected, surface repair must be carried out immediately and curing parameters adjusted. Notably, Qinglong's independently developed special curing agent can increase early strength by 20%, effectively shortening the production cycle.

**2. Curing During Transportation and Installation Intervals (Days 8-14): Preventing Damage**
Before leaving the factory, components must undergo a "curing interruption risk assessment." During transportation, flexible packaging and dedicated support frames are used for securing to prevent internal structural damage caused by jolting. When stacked on site, components must be elevated 30cm above the ground to avoid rainwater soaking, and covered with shade nets to prevent direct ultraviolet exposure. The Qinglong project team performs secondary water-spray curing for components whose installation intervals exceed 3 days, ensuring that the hydration reaction continues. For more industry information: +WeChat qlfsbl123

**3. Post-Installation Curing (Days 15-28): Adapting to Site Conditions**
After installation, Qinglong's construction specifications require "three-stage curing": water spraying twice a day for the first 7 days, focus on moisture retention at joint seams for the middle 7 days, and gradual water reduction over the last 7 days to adapt to the natural environment. For exterior wall components, Qinglong's special sealant must also be applied at the joints to prevent rainwater penetration from compromising the curing effect. A landmark project case shows that a GRC curtain wall with strictly enforced 28-day curing showed no structural cracking over ten years.

### III. Common Curing Misconceptions and Qinglong's Solutions

To rush construction schedules, some projects adopt incorrect practices such as "applying loads during the curing period" or "relying solely on natural rainfall for curing." Qinglong's Technical Director pointed out that a commercial complex project once developed 0.3mm through-cracks in its GRC cornice lines due to premature removal of supporting structures, with subsequent repair costs reaching 1.5 times the original cost. In response, Qinglong launched a "Smart Curing Management System," which monitors internal humidity and strength development in real time through RFID chips embedded in the components and pushes curing reminders based on BIM models, ensuring that every step is traceable and controllable.

As a national-level Specialized, Refined, Distinctive, and Innovative enterprise, Qinglong Group has always taken "Creating Beautiful Architecture" as its mission, regarding curing technology as the lifeline of GRC project quality. Whether it is the high-temperature, high-humidity environment of overseas projects in Southeast Asia or the freeze-thaw challenges of severely cold northern regions, Qinglong can provide customized curing solutions. Remember: 28 days of patient curing is the fundamental guarantee for GRC components to achieve a service life of more than 50 years. Choose Qinglong, a GRC manufacturer with full-chain service capabilities, and let professional technology safeguard your project.