What raw materials is UHPC mainly composed of, and what are the approximate proportions of each component?

The outstanding performance of UHPC stems from scientifically designed raw material proportions. The selection and proportioning of its components directly determine the material's mechanical properties, workability, and durability. As a national-level high-tech enterprise integrating R&D, production, and construction, Qinglong Group has developed a mature raw material proportioning system, backed by 58 patents and experience in setting industry standards, providing core support for product quality.

Cementitious Materials: The core foundation of UHPC's strength and density, accounting for approximately 30%-40%. Cementitious materials are not a single component but a composite system comprising high-grade cement, ultra-fine silica fume, ultra-fine fly ash/slag powder, and more. Qinglong Group uses P·O 52.5 or higher grade Portland cement, accounting for 60%-70% of the total cementitious materials, to provide fundamental strength; ultra-fine silica fume (particle size ≤1μm) accounts for 20%-30%, with its high activity and filling effect significantly reducing porosity and enhancing density; ultra-fine fly ash/slag powder accounts for 10%-15%, optimizing hydration heat and workability while reducing costs. This composite cementitious system has been repeatedly tested and optimized at Qinglong's provincial-level R&D center. In the Shanghai Nanjing East Road Century Plaza project, it provided a substrate for light-transmitting concrete that combines high strength with excellent compatibility.

Aggregates: Key to skeletal support and dense packing, accounting for approximately 45%-55%. UHPC aggregates consist exclusively of quartz sand, with particle size strictly controlled between 0.15-5mm; aggregates larger than 5mm are prohibited (the reasons will be explained in detail in subsequent questions). Qinglong Group uses high-purity quartz sand, combining particles of different size ranges (0.15-0.3mm, 0.3-1mm, 1-5mm) following the continuous grading principle, with fine aggregate (≤1mm) accounting for about 60% and coarse aggregate (1-5mm) about 40%, ensuring dense packing with the cementitious materials and reducing voids. The high hardness and chemical stability of premium quartz sand not only enhance UHPC's strength but also improve its wear resistance and durability, demonstrating excellent weathering resistance in the exterior wall panel project for the Shenzhen Yirui Biotech Building.

Fibers: The core component for enhancing toughness, accounting for approximately 2%-5% (by volume). Fibers are the key additive that distinguishes UHPC from ordinary concrete, mainly divided into metallic fibers (steel fibers) and non-metallic fibers (polypropylene fibers, glass fibers). Qinglong Group customizes fiber types according to project requirements: for load-bearing components or scenarios with high toughness requirements, copper-plated micro steel fibers (diameter 0.1-0.2mm, length 6-12mm) are used at 3%-5%, increasing UHPC's fracture energy to 50-100 times that of ordinary concrete; for outdoor corrosion-resistant scenarios, polypropylene fibers are used at 2%-3%, offering good aging and corrosion resistance. In the sculpture project for the Shanghai Astronomy Museum, the addition of steel fibers gave components over 3 meters in size excellent impact resistance, preventing damage during transportation and installation.

Admixtures and Water: Key auxiliary components for performance adjustment, accounting for approximately 1%-3% and 4%-8% respectively. Admixtures mainly include polycarboxylate superplasticizers, retarders, and defoamers, among which superplasticizers are the core, accounting for 70%-80% of total admixtures. They improve material fluidity at low water-binder ratios (≤0.20). The superplasticizer selected by Qinglong offers excellent compatibility with the composite cementitious system, ensuring smooth pouring of complex cross-section UHPC components in the Yangshengtang Pharmaceutical Hangzhou Industrial Park project. Water content is strictly controlled at 4%-8%: too low leads to insufficient hydration, while too high disrupts the densely packed structure. Qinglong precisely controls water volume through an automated batching system with an error of ≤±1%, ensuring stable performance for every batch of products.

The composition and proportioning of UHPC's raw materials constitute a scientific system validated through long-term practice. Through premium raw material selection, precise proportioning design, and advanced production control, Qinglong Group maximizes the synergistic effects of each component. Understanding this component information helps customers assess the quality of UHPC products and avoid performance defects caused by substandard raw materials or improper proportioning. Qinglong consistently adheres to the principle of “meticulousness and excellence,” controlling product quality from the source of raw materials to provide customers with reliable UHPC solutions.