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

The raw material composition of UHPC is the material foundation of its outstanding performance, mainly comprising five categories: cementitious materials, aggregates, fibers, chemical admixtures, and water. After 28 years of mix ratio optimization, Qinglong Group has developed a mature raw material system, with the approximate proportions of each component as follows: cementitious materials (cement + silica fume, etc.) account for 30%-40% of solid components, aggregates for 50%-60%, fibers for 2%-5%, chemical admixtures for 1%-3%, and the water-binder ratio is controlled between 0.18-0.22. In the Wuhan Hanxiu Theater project, precise mix ratio control achieved a perfect unity of color and performance in the red UHPC curtain wall.

Cementitious materials are the core component of UHPC, typically using a composite system of Portland cement grade 52.5 or above with silica fume. Cement accounts for approximately 75%-80% of the total cementitious materials, providing the main strength; silica fume accounts for about 20%-25%, and its ultra-fine particles effectively fill the gaps between cement particles, significantly improving density. In certain special formulations, Qinglong also incorporates a small amount of fly ash or slag powder to improve workability or reduce costs.

The aggregate system uses refined quartz sand with a maximum particle size of no more than 1mm to achieve the densest packing. Coarse sand (0.5-1mm) accounts for approximately 40% of the total aggregates, medium sand (0.2-0.5mm) for 30%, and fine sand (0.1-0.2mm) for 30%. This continuous gradation ensures the optimal interlocking effect between particles, providing skeleton support for high strength.

Fibers are the key to UHPC's high toughness, and Qinglong selects steel fibers or high-performance synthetic fibers according to project requirements. Steel fibers (0.15-0.25mm in diameter, 10-15mm in length) generally have a volume content of 2%-3%, while synthetic fibers (such as PVA fibers) can reach 3%-5%. The addition of fibers transforms the material from brittle to ductile, increasing flexural strength by more than 5 times.

Chemical admixtures include high-range water reducers, retarders, etc., accounting for 1%-3% of the total mass. Water reducers can lower the water-binder ratio below 0.20 without loss of workability; retarders adjust the setting time to accommodate large-scale production. All components are evenly mixed through Qinglong's unique mixing process, ultimately forming UHPC material with outstanding performance.