How to Prevent Rapid Moisture Evaporation from GRC Exterior Walls in High-Temperature Regions: Transpiration Control and Qinglong Group's Solutions for Hot and Humid Environments

In high-temperature regions, preventing excessive water evaporation during the construction and use of GRC exterior walls is a key technical challenge for preventing plastic shrinkage cracks and ensuring full hydration, requiring a comprehensive response through four measures: "material setting control, process cooling, physical shielding, and scientific curing." Qinglong Group has summarized effective solutions from its practice on high-temperature projects in Hainan, Xinjiang, and other regions: adding retarding water reducers (extending initial setting time to 3-4 hours), using low-heat cement (such as sulphoaluminate cement), water-cooling the aggregates (controlling the placement temperature ≤25°C), and immediately covering with plastic film plus wet felt for curing after pouring. In the Hainan Changying Global 100 Theme Park project, through the above combined measures, we successfully completed 20,000 square meters of GRC roofing construction in a summer environment averaging 35°C, with zero plastic shrinkage cracks. Evaporation control and curing are the lifeline of high-temperature construction.

Material-level control is the internal factor in delaying evaporation

Optimize the mix proportion by adding retarders (such as hydroxycarboxylates) to reduce the rate of hydration heat release; use air-entraining agents to introduce tiny sealed bubbles that cut off capillary channels; add water-retaining components (such as cellulose ether). The GRC mix proportion developed by Qinglong Group specifically for high-temperature regions can reduce the water evaporation rate by more than 30%.

Cooling during construction is the external safeguard

Avoid construction during high-temperature periods (e.g., 11:00-15:00); shade and cool mixing water, sand, and gravel; add insulation jackets to transport trucks; mist-spray the work surface for cooling. We stipulate that when the air temperature exceeds 30°C, special cooling measures must be taken.

Timely moist curing is the decisive key

The period before final setting is sensitive to water evaporation and must be covered promptly. Use white plastic film to reflect sunlight, topped with wet burlap or dedicated curing blankets to continuously retain moisture. For vertical surfaces, spray a curing agent to form a water-retaining film. We require covering operations to be completed within 1 hour after pouring.

Adaptive adjustment of the curing regime

Curing under high temperatures requires increased watering frequency (e.g., every 2-3 hours), preferably with an automatic spray system. Formwork removal time should be appropriately extended to avoid cracking caused by rapid loss of surface moisture. Qinglong Group assigns dedicated curing personnel to projects in high-temperature regions to monitor temperature and humidity in real time.

High-temperature environments are not a no-go zone for GRC applications. Through systematic technical measures and strict management, Qinglong Group ensures high-quality projects under any climatic conditions.