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

The outstanding performance of UHPC (Ultra-High Performance Concrete) stems from its precise raw material system. As a professional manufacturer with 28 years of deep industry experience, Qinglong UHPC can clearly answer based on extensive experimental data and engineering practice: the formula of premium UHPC 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 a super high-rise project in Qianhai, Shenzhen, the raw material system adopted by Qinglong UHPC is representative: Grade 52.5 low-alkali cement (alkali content ≤0.6%) provides the strength foundation; micro silica fume (SiO₂ content ≥92%) fills micro-pores; selected quartz sand (maximum particle size 0.6mm) forms the skeleton; hooked-end steel fibers (tensile strength ≥2850MPa) enhance toughness; polycarboxylate superplasticizer (water reduction rate ≥35%) improves workability. This precise mix proportion keeps the compressive strength stable above 150MPa and the flexural strength at 22MPa, providing reliable material assurance for the project.

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 ≥15000㎡/kg) fills micro-pores and enhances 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.

Key Technologies of the Reinforcing Fiber System

Copper-plated steel fibers (13mm long, 0.2mm in diameter) are used at a volume fraction of 2%-3% with an aspect ratio of 60-80; surface treatment improves the bond between fibers and the matrix; fibers of different scales work synergistically to effectively prevent crack propagation. This reinforcement system enables the material to achieve an ultimate tensile strain of over 0.3%.

Optimized Configuration of the Aggregate System

Selected quartz sand has a maximum particle size of ≤0.6mm, a fineness modulus of 1.8-2.2, and a mud content of ≤0.3%; grading is optimized through maximum packing density theory, reducing the aggregate void ratio to below 20%. In the dense packing system, the aggregate volume fraction can reach 40%-45%.

Precise Control of Chemical Admixtures

The polycarboxylate superplasticizer has a water reduction rate of ≥35%, ensuring workability at low water-binder ratios; defoamers control the air content at ≤2%; retarding components adjust the setting time. Through precise proportioning, these admixtures achieve optimal control of material performance.

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