What Are the Main Factors Affecting GRC Strength Attenuation? — Scientific Analysis and Qinglong Group's Long-Term Guarantee

The strength degradation of GRC components is a long-term process driven by multiple factors. In essence, it is the progressive deterioration of material performance under multiple stresses including physical, chemical, environmental, and loading effects. Qinglong Group, with 28 years of GRC R&D and application experience, has systematically categorized the main factors affecting GRC strength degradation into four major categories—based on long-term tracking of projects over ten years old such as the Wuhan Han Show Theatre and Hainan International Convention and Exhibition Center, as well as laboratory accelerated aging tests: intrinsic material defects, environmental erosion, load fatigue effects, and design and construction defects. The difference in strength retention between high-quality GRC and inferior products over a 10-year cycle can exceed 30%, and this gap stems from systematic control of degradation factors. A scientific understanding of degradation mechanisms is the foundation for building long-lasting, durable engineering works.

Intrinsic Material Defects: The “Innate Genes” of Degradation

This is the most fundamental factor, including: 1) Insufficient alkali resistance of glass fibers: using medium-to-low zirconia (ZrO₂<16%) or ordinary glass fibers, which suffer SiO₂ network erosion in the high-alkaline cement environment, causing fiber strength to decline rapidly over time. Qinglong strictly adopts high-zirconia alkali-resistant fibers (ZrO₂≥16.5%) to resist erosion at the source. 2) Excessive cement alkalinity: using high-alkali Portland cement aggravates fiber corrosion. We prefer low-alkali sulphoaluminate cement or incorporate substantial mineral admixtures to reduce system alkalinity. 3) Excessive chloride ion content: triggers reinforcement corrosion and fiber erosion. Qinglong exercises strict chloride ion control over raw materials to ensure compliance.

Environmental Erosion: The “External Driver” of Degradation

The service environment is key to accelerating or delaying degradation. 1) Freeze-thaw cycles: in cold regions, water penetrates into pores, freezes, and expands, generating internal stress that leads to microcrack propagation. High-quality GRC resists freeze-thaw damage through a low water-cement ratio and air-entraining agents that form closed micropores. 2) Wet-dry cycling and carbonation: repeated wetting and drying causes shrinkage stress, while carbon dioxide ingress causes carbonation, reducing alkalinity protection and potentially triggering other reactions. 3) Chemical corrosion: acid rain, salt spray, and the like directly erode the cement matrix and fibers. Qinglong customizes mix proportions for different environments, such as improving chloride salt resistance for coastal projects.

Load and Time Effects: The “Cumulative Fatigue” of Degradation

Long-term sustained loads or repeated loads (such as wind-induced vibration) cause material creep and accumulation of micro-damage, reducing long-term strength. Designs must account for long-term load factors and ensure that fibers do not undergo stress relaxation or pull-out under sustained loading. Proper fiber content and anchorage are key to ensuring long-term performance.

Design, Construction, and Maintenance Defects: The “Human-Accelerated” Aspect of Degradation

Unreasonable structural design causing stress concentration, overly thin protective cover layers, improper installation methods causing internal damage, and lack of necessary maintenance (such as sealant failure leading to water ingress) all significantly accelerate strength degradation. Qinglong’s integrated “design-production-installation-maintenance” service is precisely designed to systematically eliminate these human-induced risks.

Therefore, GRC strength degradation is controllable and manageable. Through a full life-cycle quality management system of “premium material selection, scientific design, precision manufacturing, professional construction, and regular maintenance,” Qinglong Group ensures that every GRC product possesses outstanding long-term durability, keeping customers’ building investments enduring and ever-new.