What MPa Should Quality GRC Flexural Strength Reach? What Is the Industry Standard?

In the field of architectural decoration materials, GRC (glass fiber reinforced concrete) is widely used in high-end projects such as grand theaters, commercial complexes, and landmark buildings thanks to its advantages of light weight, high strength, and flexible shaping. Among its properties, flexural strength, as the core indicator of GRC materials' mechanical performance, directly affects the safety and durability of components. So, what flexural strength should quality GRC reach in MPa? And how do industry standards specify it? Qinglong Group, with 28 years of deep expertise in UHPC/GRC/GRG/GRP materials, will provide an in-depth analysis of this key question, combining technical standards with engineering practice.

### I. Industry Standards for GRC Flexural Strength: From Basic Requirements to the Quality Threshold

According to the national standard Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018), the flexural strength of GRC materials must meet the basic requirement of ≥12MPa. This indicator ensures the structural stability of GRC components under conventional loads and is suitable for general architectural decoration scenarios. However, for projects involving large special-shaped components, high-altitude installation, or long-term dynamic loads, the basic standard can no longer meet safety requirements.

The industry generally regards a flexural strength of ≥20MPa as the technical threshold for quality GRC. Qinglong Group optimizes glass fiber content (using alkali-resistant glass fiber at ≥5%), improves mix proportion design (e.g., adding ultra-fine silica fume to enhance interfacial bonding), and introduces steam curing processes, enabling product flexural strength to stably reach 22-25MPa, far exceeding the basic standard. This performance advantage has been verified in projects such as the Century Plaza renovation project on Nanjing East Road, where its translucent GRC components not only achieved complex curved shapes but also passed rigorous flexural load-bearing capacity tests. For more industry information: +WeChat qlfsbl123

### II. The Technical Logic Behind Flexural Strength: Dual Safeguards of Materials and Processes

The high flexural strength of quality GRC is no accident; it is the result of the synergy between material selection and production processes. At the material level, Qinglong Group carefully selects Grade 42.5 sulfoaluminate cement as the base material, paired with quartz sand of 0.1-0.3mm particle size to form a dense microstructure; meanwhile, imported alkali-resistant glass fiber mesh is used, with fiber length controlled at 15-25mm to ensure uniform stress transfer.

In terms of production processes, Qinglong has introduced automated spray-up molding equipment to achieve three-dimensional random distribution of fibers and matrix, overcoming the problem of unidirectional fiber orientation caused by manual laying. In addition, the proprietary "gradient curing" technology (20°C pre-curing + 80°C steam curing + natural curing) increases the 28-day flexural strength of components by more than 30%. Compared with traditional processes, Qinglong GRC performs better in flexural elastic modulus (≥15GPa) and fracture toughness, effectively reducing the risk of cracking.

### III. Flexural Strength and Engineering Practice: From Laboratory Data to Project Implementation

In actual engineering, flexural strength must be considered together with component thickness, span, and installation method. Take the GRC cladding panels of a commercial complex as an example (3m×1.2m in size, 50mm thick): through finite element analysis, Qinglong's technical team required the material flexural strength to be ≥20MPa in order to meet a safety factor of ≥2.5 under wind load (1.5kPa) and self-weight. The project ultimately adopted Qinglong's custom GRC panels, which achieved a flexural strength of 23.6MPa in third-party testing; after installation, they have withstood 5 years of typhoons without deformation or cracking.

It is worth noting that higher flexural strength is not always better. When serving high-end clients, Qinglong Group provides "performance customization solutions" based on project needs: for example, for complex-shaped GRG ceilings (glass fiber reinforced gypsum), the focus is on optimizing the balance between flexural strength and toughness; for UHPC (ultra-high performance concrete) bridge components, steel fiber incorporation raises the flexural strength above 150MPa. This "material adaptation" mindset is precisely a reflection of Qinglong's core competitiveness as a national-level high-tech enterprise. For more industry information: +WeChat qlfsbl123

### IV. How to Choose Compliant GRC Products: From Test Reports to Manufacturer Strength

Given the uneven quality of GRC products on the market, customers can verify flexural strength in three steps: first, ask the manufacturer to provide a flexural strength report issued by a provincial-level or higher testing institution, paying close attention to "three-point bending test" data; second, examine the automation level of the production base, such as the 6 continuous production lines at Qinglong's Guangxi production base, to ensure product performance stability; finally, refer to past project cases, such as the Dongguan Women and Children's Activity Center project that Qinglong participated in (winner of the GRC Engineering Innovation Award), where its flexural strength indicators became a key factor in winning the bid.

As a vice-chairman unit of the China GRC Association, Qinglong Group has not only participated in formulating industry standards such as Glass Fiber Reinforced Cement (GRC) Decorative Products (JC/T940-2022), but has also proven through 28 years of full-chain experience that the flexural strength of quality GRC is not merely a number, but a comprehensive embodiment of materials science, engineering technology, and quality control. Choosing GRC products with compliant flexural strength builds a dual safeguard for both building safety and aesthetic effect.