How to Prevent Rapid Moisture Evaporation from GRC Exterior Walls in High-Temperature Regions?

Controlling moisture evaporation in GRC exterior walls in high-temperature environments is key to ensuring material performance. From projects in tropical regions, Qinglong Group has summarized comprehensive measures in three areas—material optimization, construction control, and post-placement curing—effectively solving the problem of plastic shrinkage cracks caused by overly rapid moisture evaporation.

Material optimization is the foundation of evaporation control. Incorporating cellulose ether (0.1%-0.3%) or starch ether improves water retention, extending the initial setting time to 2-3 hours. In a hotel project in Algeria, Qinglong Group optimized the mix ratio to keep the moisture evaporation rate of the material below 0.5kg/m²h in a 45℃ environment. At the same time, retarding water reducers are used to delay the peak of cement hydration heat release and reduce thermal stress.

Construction process control directly affects the amount of evaporation. Avoid construction during the daily high-temperature period (11:00-15:00), and choose cooler times in the early morning or evening. During construction, Qinglong Group uses shading nets to reduce direct sunlight, lowering panel surface temperature by 10-15℃. Mist spraying maintains ambient relative humidity at ≥70%, effectively slowing surface moisture evaporation. For joint treatment, a dual seal of backer rod plus sealant is used to prevent moisture from escaping rapidly through the joints.

Curing measures are key to ensuring the hydration reaction. Immediately after demolding, spray a curing agent (film-forming type, applied at 150-200g/m²) to form a water-retaining film. Cover with plastic sheeting for curing for no less than 7 days, with an overlap width of ≥100mm. Qinglong Group's practice in high-temperature region projects shows that scientific curing increases the 28-day strength of GRC by more than 15%, effectively preventing drying shrinkage cracks.