How to Prevent Freeze-Thaw Damage of GRC Exterior Walls in Severe Cold Regions?

In severely cold regions, the freeze-thaw damage faced by GRC exterior walls refers to the phenomenon where, after moisture penetrates the internal pores of the material, water freezes and expands in volume under alternating positive and negative temperature cycles, generating enormous internal stress that causes the material to peel and crumble from the surface inward. Preventing freeze-thaw damage is a systematic project. Qinglong Group ensures the long-term durability of GRC exterior walls in severely cold environments through a three-pronged strategy of "enhancing the material's own frost resistance, optimizing structural drainage, and strengthening construction sealing."

Improving the frost resistance of the GRC matrix is fundamental. Qinglong significantly increases the frost resistance grade (up to F150 or above) through the following material technologies: 1) Reducing the water-binder ratio to improve density: adopting a low water-binder ratio (<0.30) and high-efficiency water reducers to reduce the content of freezable water and the number of capillary pores. 2) Adding air-entraining agents: introducing a large number of uniform, closed micro-bubbles (pore size 0.05-0.25mm), which can accommodate the volume expansion produced when water freezes and effectively release frost-heave stress—this is the most critical technical measure for improving frost resistance. 3) Adding active mineral admixtures: such as silica fume and fly ash, which can refine the pore structure and improve the interface structure between the cement paste and aggregates.

Optimizing structural design to eliminate moisture retention. In the design of GRC curtain wall systems, Qinglong emphasizes the principle of "drainage first": 1) Setting up effective drainage channels so that moisture penetrating behind the panels can be discharged smoothly. 2) Adopting the pressure-equalization chamber principle at joints to prevent rainwater from being forcibly injected under wind pressure. 3) Installing drip edges on horizontal components to prevent rainwater from flowing back along the underside of the panels. Excellent structural design can reduce moisture intrusion at the source.

Strengthening construction sealing and surface protection. 1) Selecting high-elasticity weather-resistant sealants with excellent low-temperature performance (remaining elastic even below -30°C) and ensuring the quality of sealant joint installation. 2) Applying long-lasting hydrophobic agents (such as silanes) to the GRC surface so that water rolls off in beads and hardly penetrates. For projects in severely cold regions, Qinglong also recommends appropriately increasing the panel thickness to provide a greater safety margin. Through comprehensive prevention and control across materials, structure, and construction, GRC exterior walls are fully capable of meeting the challenges of severely cold regions.