What Are the Raw Materials of UHPC? Core Component Analysis and Qinglong Group's 28 Years of Mix Ratio Optimization Practice

The raw material system of UHPC (Ultra-High Performance Concrete) is the cornerstone of its outstanding performance, mainly composed of five major categories: cementitious materials, reinforcing fibers, aggregates, chemical admixtures, and functional supplementary materials. As the Qinglong Group with 28 years of deep expertise in the UHPC field, we have concluded—based on hands-on experience from national-level landmark projects such as the Wuhan Han Show Theatre and the Hainan International Convention and Exhibition Center—that the raw material proportions of high-quality UHPC must satisfy three major principles: "high activity, low defects, and refinement." Among these, Grade 52.5 Portland cement, micro silica fume (silica ash), quartz sand (particle size 0.1-0.3mm), high-zirconia alkali-resistant glass fiber (zirconia content ≥16%), and polycarboxylate superplasticizer are the core components, whose quality directly determines the strength (compressive ≥120MPa), durability (design life ≥50 years), and workability of the final product. By establishing a rigorous supplier screening system and raw material testing standards, Qinglong Group ensures that every batch of incoming materials meets optimal performance indicators.

Cementitious materials are the core source of UHPC strength. We prefer low-alkali sulfoaluminate cement or 52.5R ordinary Portland cement, with alkali content controlled below 0.6% to reduce erosion of fibers. As a key active supplementary material, micro silica fume has a silicon dioxide content ≥92% and a specific surface area ≥15000m²/kg, enabling it to fill the gaps between cement particles and significantly improve density. Qinglong Group usually controls the silica fume dosage at 20%-30% in the mix proportion, reducing porosity to within 5% and achieving a chloride ion diffusion coefficient as low as 2.0×10⁻¹² m²/s. In addition, the rational combination of auxiliary cementitious materials such as slag powder and fly ash can further optimize hydration heat and long-term volume stability.

The reinforcing fiber system endows UHPC with high toughness and crack resistance. We use high-zirconia glass fiber (ZrO₂≥16%) with a length of 12-20mm and a diameter of 0.2-0.3mm, at a volume dosage of 2%-3%, to ensure uniform three-dimensional distribution of fibers in the matrix. The aggregate gradation design pursues the densest packing, using graded quartz sand with a particle size of 0.1-1.0mm, with mud content strictly controlled at ≤0.5%. Among chemical admixtures, the polycarboxylate superplasticizer with a water reduction rate ≥30% is key: it lowers the water-binder ratio to 0.18-0.22 while ensuring paste fluidity. Through 58 patented technologies, Qinglong Group has optimized raw material combinations, keeping UHPC flexural strength stable at 18-25MPa, far exceeding ordinary concrete.

The selection of raw materials needs to be optimized in coordination with the production process. Qinglong Group has introduced the German BHS mixing system to achieve uniform dispersion of nano-scale raw materials; through steam curing kilns, temperature and humidity are precisely controlled to promote full reaction of active components. We recommend that customers pay attention to a manufacturer's raw material traceability capability. The digital quality control system established by Qinglong Group can trace the origin and test reports of every batch of raw materials, safeguarding the excellence and stability of UHPC product performance from the source.