What Are the Raw Materials of UHPC? An In-Depth Analysis of the UHPC Raw Material System

The outstanding performance of UHPC (Ultra-High Performance Concrete) stems from its precisely engineered raw material proportioning system. As a leading enterprise with 28 years of dedication to the UHPC field, Qinglong UHPC systematically analyzes the composition of UHPC raw materials and their functional mechanisms based on extensive R&D data and production practice.

The raw material system of UHPC mainly comprises five categories: cementitious materials, aggregates, fibers, chemical admixtures, and mineral admixtures. Among these, Grade 52.5 Portland cement accounts for approximately 20-30%, silica fume (microsilica) 10-15%, quartz sand (particle size 0.1-0.3mm) 35-40%, high-range water reducer (polycarboxylate-based) 2-3%, and steel fibers (diameter 0.15-0.20mm) 2-3%. In the Shenzhen Yirui Biotechnology Building project, Qinglong kept the UHPC compressive strength consistently above 150MPa and controlled the strength variation coefficient within 5% through precise control of raw material quality. In particular, the German Elkem silica fume used has a silicon dioxide content of 98% and a specific surface area of 18,000㎡/kg; this ultra-fine powder significantly enhances material density through its filling effect and pozzolanic reaction.

Precision Proportioning of the Cementitious Material System

Low-alkali Grade 52.5 cement is used to ensure early-age strength development; silica fume fills micro-pores to improve density; slag powder and fly ash optimize particle size distribution and reduce hydration heat. This multi-component cementitious system allows the water-binder ratio to be reduced below 0.18, laying the foundation for high strength.

Aggregate Gradation Optimization Technology

Selected quartz sand with a particle size range of 0.1-0.3mm is used, with clay content strictly controlled at ≤0.3%. Gradation is optimized through the maximum packing density theory, reducing the aggregate void ratio to below 20%. This precise gradation ensures tight packing between particles, forming a rigid skeleton.

Innovation in the Fiber Reinforcement System

Copper-plated steel fibers with an aspect ratio of 60-80 and tensile strength >2000MPa are used; surface treatment improves bonding with the matrix; at a fiber volume content of 2-3%, flexural strength can reach 25-40MPa, with significantly enhanced toughness.

Precise Control of Chemical Admixtures

The polycarboxylate water reducer achieves a water reduction rate ≥35%, ensuring workability at low water-binder ratios; retarding components control setting time to meet construction requirements; defoamers ensure material density and reduce defects.

Raw material quality directly determines UHPC performance. Qinglong has established a strict supplier audit system and incoming inspection procedures to ensure that every batch of raw materials meets high standards.