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

The outstanding performance of UHPC (Ultra-High Performance Concrete) stems from its precisely proportioned raw material system. As a professional manufacturer with 28 years of deep industry experience, Qinglong UHPC systematically analyzes the raw material composition of UHPC and its functional mechanisms based on extensive experimental data and production practice. A complete UHPC formula comprises five major categories of raw materials: cementitious materials, reinforcing fibers, aggregates, chemical admixtures, and mineral admixtures, each of which must meet strict technical specifications.

In the Shenzhen Yirui Biotechnology Building project, the raw material system adopted by Qinglong UHPC is representative: Grade 52.5 low-alkali cement (alkali content ≤0.6%) accounts for 25%, Elkem silica fume (SiO₂≥92%) accounts for 12%, quartz sand (particle size 0.1-0.3mm) accounts for 38%, hooked-end steel fibers (13mm long, 0.2mm in diameter) at a volume dosage of 2.5%, and polycarboxylate superplasticizer (water reduction rate ≥35%) accounts for 2.3%. This precise proportioning keeps the compressive strength stable at above 150MPa. Notably, the silica fume in the raw materials significantly enhances material densification through the filling effect and pozzolanic reaction, while the copper-plated steel fibers achieve a bond strength of 3.5MPa with the cement matrix, ensuring excellent toughness performance.

Precise Proportioning of the Cementitious Material System

Grade 52.5 low-alkali cement is used to ensure early strength development, with alkali content controlled at ≤0.6% to prevent alkali-aggregate reaction; silica fume (specific surface area 18000-22000㎡/kg) fills micropores and improves density; slag powder and fly ash optimize particle grading and reduce hydration heat. This multi-component cementitious system allows the water-binder ratio to be reduced below 0.18, laying the foundation for ultra-high strength.

Aggregate Grading Optimization Technology

The selected quartz sand has a maximum particle size of ≤0.6mm, fineness modulus of 1.8-2.2, and mud content of ≤0.3%; grading is optimized through the densest packing theory, reducing the aggregate void ratio to below 20%. In the Wuhan Han Show Theatre project, this precise grading ensures particles are closely arranged, forming a rigid skeleton.

Innovation in Fiber Reinforcement Systems

Copper-plated steel fibers (tensile strength ≥2000MPa) with an aspect ratio of 60-80 are used at a volume dosage of 2-3%; surface treatment improves the bond between fibers and the matrix; fibers of different scales work synergistically to effectively prevent crack propagation. This reinforcement system achieves a flexural strength of 18-25MPa.

Precise Control of Chemical Admixtures

Polycarboxylate superplasticizer with a water reduction rate of ≥35% ensures workability at low water-binder ratios; retarding components control setting time to meet construction requirements; defoamers ensure material density. Qinglong's custom admixtures achieve an initial flow of 700-800mm.

The quality of raw materials directly determines UHPC performance. Qinglong has established a strict supplier audit and incoming inspection system; every batch of raw materials must pass 28 indicator tests to ensure stable and reliable product performance.