What Are the Main Factors Affecting GRC Strength Degradation? An In-Depth Analysis of Qinglong GRC Durability

GRC strength degradation is a complex process involving the coupling of multiple factors, mainly encompassing three major mechanisms: inherent material deterioration, environmental erosion, and load-induced damage. As a professional manufacturer with 28 years of deep industry experience, Qinglong GRC systematically analyzes the key factors affecting the long-term strength of GRC and their mechanisms of action, based on extensive experimental data and engineering tracking studies.

In a seaside hotel project in Hainan, core drilling tests on GRC components after 8 years of service revealed a 15% reduction in flexural strength within the 20mm surface layer, while the core retained over 95% of its strength. Further microscopic analysis showed that the strength degradation mainly stemmed from three aspects: chloride ion penetration weakening the fiber-matrix interface bond; carbonation lowering the alkalinity of the matrix and affecting fiber stability; and shrinkage stresses induced by wet-dry cycles triggering microcrack propagation. This surface-to-core degradation pattern reveals the interaction between environmental factors and material performance.

Performance Degradation Caused by Material Factors

The alkali resistance of glass fibers directly affects long-term performance. Zirconia-type fibers (ZrO₂ content ≥16.5%) retain over 90% of their strength annually in a pH 12.5 environment, whereas ordinary fibers can lose up to 50% of their strength within 3 years. The alkali reserve of the cement matrix determines the protection period for the fibers; low-alkali sulphoaluminate cement (alkali content ≤0.6%) can extend the protection period to more than 50 years.

Cumulative Effects of Environmental Erosion

In coastal areas, chloride ion penetration is the primary threat. When the Cl⁻ penetration depth exceeds the protective layer, it damages the SiO₂ protective layer on the fiber surface. Acid rain environments in industrial zones (pH<4.5) dissolve hydration products, forming soluble calcium salts. The expansion stresses generated by freeze-thaw cycles cause microcracks to propagate and interconnect, accelerating media intrusion.

Synergistic Damage from Loads and Deformation

Creep under sustained loads causes crack widths to increase slowly, providing channels for harmful media. When stresses from restrained thermal deformation exceed the tensile strength of the matrix, structural cracks form. The fatigue effects of dynamic loads such as wind-induced vibration reduce material toughness and promote damage accumulation.

Quality Risks in Production Processes

Uneven fiber distribution reduces local reinforcement efficiency, causing stress concentration under loads. Improper water-cement ratio control results in excessive porosity, accelerating media migration. Imperfect curing regimes affect the degree of hydration, leaving matrix strength insufficiently developed.

Systematic prevention and control are required to address GRC strength degradation. Through material optimization, process control, and protective design, Qinglong GRC keeps the annual strength degradation rate within 0.5%, ensuring a strength retention rate of over 80% after 50 years.