Key Technical Points and Implementation Strategies for Steam Curing of GRC Components in Low-Temperature Environments

Key Technical Points and Implementation Strategies for Steam Curing of GRC Components in Low-Temperature Environments

In the field of architectural decorative materials, GRC (Glass Fiber Reinforced Concrete) is widely used in high-end buildings such as grand theaters and commercial complexes thanks to its lightweight, high-strength properties and rich modeling capabilities. However, production and curing in low-temperature environments has long been an industry pain point, directly affecting the strength development and durability of components. As a group with 28 years of experience in GRC detailed design and production, Qinglong Group, drawing on the technical expertise accumulated as a national-level high-tech enterprise, has developed a systematic steam curing solution, providing professional technical support for GRC projects in cold regions.

I. Impact Mechanism of Low-Temperature Environments on GRC Components

When the ambient temperature falls below 5℃, the hydration reaction rate of GRC slows significantly, easily leading to problems such as slow strength gain and surface cracking. Under low-temperature conditions, traditional natural curing requires more than 7 days to reach 70% of the design strength, severely limiting production efficiency. Through comparative experiments, the Qinglong technical team found that GRC specimens kept at -5℃ without curing measures achieved only 62% of the 28-day strength of standard curing, while scientific steam curing can raise the 3-day strength to over 85% of the design value, effectively solving low-temperature construction challenges.

II. Key Technical Parameters of the Steam Curing Process

The Qinglong GRC production line adopts an intelligent temperature-controlled steam curing system, with the following core control points:

1. Preheating stage: Raise the component temperature to 40℃ at a heating rate of 5-10℃/h to avoid internal stress caused by sudden temperature changes. Relative humidity must be kept at ≥90% during this stage to prevent surface moisture from evaporating too quickly.

2. Constant temperature stage: Maintain 60-65℃ for 4-6 hours; this temperature range maximizes the cement hydration reaction while preventing damage to glass fibers from high temperatures (Qinglong's patented formula can withstand short-term curing at 70℃).

3. Cooling stage: Strictly control the cooling rate at ≤10℃/h; curing may be terminated only when the temperature difference between the component and the environment is ≤20℃. Combined with Qinglong's self-developed curing kiln insulation technology, energy consumption is reduced by 18% compared with traditional processes.

III. Curing Implementation Strategies Specific to Low Temperatures

For severely cold regions, Qinglong has innovatively adopted the "dual-circulation curing method":

• Internal circulation: Large components are heated internally through embedded steam pipes, ensuring uniform temperature in thick-walled parts (such as Roman columns and shaped reliefs) and solving the problem of traditional curing, where surfaces overheat while interiors are under-cured.

• External circulation: An intelligent steam generator combined with a curing cover forms a closed-space circulation system. Even at -15℃, it can maintain a constant 55℃ inside the curing chamber, saving 25% more energy than conventional industry equipment.

In addition, Qinglong's low-temperature-specific GRC formula, which incorporates early-strength mineral admixtures and antifreeze agents, keeps the initial setting time of concrete within 6 hours at 5℃, creating favorable conditions for steam curing.

IV. Quality Control and Engineering Evidence

As a contributing drafting unit of the Technical Standard for Architectural Application of Glass Fiber Reinforced Cement (GRC), Qinglong has established a full-process quality traceability system: RFID chips are embedded in each batch of components to record temperature and humidity curves throughout the curing process. In an ice-and-snow theme park project in Harbin, this technology enabled GRC curtain wall components to achieve a 100% first-pass acceptance rate under construction conditions of -20℃, finishing 12 days ahead of the contract schedule.

Qinglong Group has been deeply engaged in the GRC/GRG/UHPC field for 28 years. With an annual production capacity of 600,000 ㎡ at its production base in Nanning, Guangxi, it provides customers with full-chain services from detailed design to after-sales maintenance. Whether for municipal projects in severely cold regions or overseas projects in high-humidity environments, Qinglong has always followed the philosophy of "meticulous workmanship and the pursuit of excellence," delivering professional and reliable material solutions for the architectural decoration industry. For more details on GRC low-temperature construction technology, please follow the Qinglong technical white paper series.