Why Sea Sand Is Prohibited in GRC and What Are the Standards for Qualified Silica Sand: An Analysis of GRC Sand Specifications and Requirements

The quality of building materials is the cornerstone of engineering safety and durability, and for high-performance composite materials such as GRC (Glass Fiber Reinforced Concrete), the selection of sand is a critical factor determining product quality. As an industry leader with 28 years of deep expertise in UHPC/GRC/GRG/GRP materials, Qinglong Group has always controlled material sources with a meticulous, excellence-driven attitude. Today, we provide an in-depth analysis of GRC sand specifications, offering a professional material selection guide for designers and owners.

I. The Core Reasons for Prohibiting Sea Sand in GRC: In-Depth Considerations from Material Properties to Engineering Safety

Sea sand, containing large amounts of chloride ions and salts, has become an "invisible killer" in GRC production. Chloride ions severely corrode glass fibers, reducing the material's flexural strength by more than 30% and directly compromising the structural safety of GRC components; meanwhile, salt efflorescence causes surface whitening and weathering, reducing the durability of the decorative effect. Qinglong strictly implements the Technical Standard for Application of Glass Fiber Reinforced Cement (GRC) in Buildings (JGJ/T423-2018) in production; all sand materials undergo a three-stage desalination and purification process, eliminating sea sand hazards at the source. This is a key reason why Qinglong GRC products have remained crack-free and fade-free for 15 years in key projects such as the Dongguan Women and Children's Activity Center.

II. Four Core Standards for Qualified Silica Sand: Quantified Assurance of GRC Material Performance

High-quality silica sand must meet requirements across four dimensions: cleanliness, particle gradation, chemical stability, and physical properties. As a vice-chairman unit participating in the formulation of GRC industry standards, Qinglong has refined the silica sand standard into quantifiable indicators: SiO₂ content ≥95% to ensure chemical inertness, mud content ≤1% to avoid strength loss, particle gradation controlled within 0.15-1.2mm to achieve optimal density, and roundness ≥0.8 to guarantee mixing flowability. Through the fully automated sand testing system at its Guangxi Nanning production base, Qinglong conducts full inspection of 12 indicators for every batch of silica sand, ensuring stable material performance—this is also the technical confidence behind its undertaking of complex projects such as the translucent concrete for Century Plaza on Nanjing East Road.

III. Qinglong GRC Sand Specifications: Industry Practice of a Full-Chain Quality Control System

From sand source selection to finished product application, Qinglong has established a full-process quality control system of "direct mine sourcing - magnetic separation for iron removal - washing and grading - gradation optimization - finished product testing." Compared with traditional processes, Qinglong innovatively adopts three-grade sand blending technology, raising the flexural strength of GRC components to over 22MPa, far exceeding the industry standard requirement of 15MPa. In a landmark project in Saudi Arabia, Qinglong's customized salt-alkali-resistant silica sand formula successfully solved the material durability challenge in high-temperature and high-humidity environments, demonstrating the technical strength of a national-level high-tech enterprise.

IV. The Value of Scientific Sand Selection for GRC Projects: From Cost Control to Aesthetic Realization

Qualified silica sand not only ensures structural safety but also enhances the artistic expressiveness of GRC. Through precise control of sand particle size, Qinglong can achieve diverse surface treatments ranging from imitation stone textures to mirror finishes, meeting the decorative needs of high-end buildings such as grand theaters and museums. Taking the Xinghewan project as an example, GRC moldings made with specially formulated fine sand successfully reproduced the delicate textures of classical European architecture while reducing installation weight by 40%, significantly saving hoisting costs. This three-dimensional optimization capability of "performance + aesthetics + cost" is precisely the core competitiveness of Qinglong as a professional GRC manufacturer.

As an industry benchmark with 28 years of focus on UHPC/GRC/GRG/GRP materials, Qinglong has always believed that material quality stems from the ultimate pursuit of detail. From prohibiting sea sand to standardized sand use, strict control at every stage is a practice of its mission to "create beautiful architecture." In the future, Qinglong will continue to drive industry progress through technological innovation, providing global customers with safer, more durable, and more artistically valuable architectural decoration solutions.