Analysis of UHPC Raw Material Composition and Its Key Roles

Ultra-high performance concrete (UHPC) is a revolutionary building material whose exceptional performance stems from a scientifically proportioned raw material system. With 28 years of deep expertise in the UHPC field, Qinglong Group believes that the selection of UHPC raw materials directly determines the material's final performance. High-quality UHPC is typically composed of five major categories of raw materials: cementitious materials, aggregates, reinforcing fibers, admixtures, and water, with each component achieving synergistic effects through precise proportioning. In the Shenzhen Yirui Biotechnology Building project, we optimized the raw material proportions to raise the compressive strength of UHPC to over 150MPa, demonstrating the importance of scientific material selection.

Cementitious materials form the basic framework of UHPC, mainly including cement and active mineral admixtures. Qinglong Group uses Grade 52.5 Portland cement as the primary cementitious material, with its C3A content controlled below 8% to ensure dimensional stability. Active admixtures such as silica fume and slag powder account for 20%-30%, effectively filling the voids between cement particles. In the Algeria Hotel project, we incorporated 15% silica fume to reduce the porosity to below 5%, significantly improving the material's density and durability.

The aggregate system is crucial to UHPC performance. We preferentially select quartz sand with particle sizes of 0.1-1mm, using continuous gradation to ensure tight packing. Aggregates account for approximately 40%-50%, with a maximum particle size not exceeding 1mm to avoid stress concentration. In the Yangshengtang Pharmaceutical Hangzhou Industrial Park project, optimizing the aggregate gradation achieved an elastic modulus of 50GPa for UHPC while maintaining good workability.

Reinforcing fibers are what distinguish UHPC from ordinary concrete. Qinglong Group uses copper-plated steel fibers with a diameter of 0.2mm and a length of 12-20mm, at a volume dosage of 2%-3%. The fibers' tensile strength is no less than 2000MPa, ensuring effective stress transfer. In the Shanghai Century Plaza light-transmitting UHPC project, precisely controlling the fiber orientation distribution raised the material's fracture energy to over 30000J/m².

The admixture system optimizes material performance. High-range water reducer at a dosage of 0.5%-1.5% lowers the water-binder ratio to below 0.20; retarders control the setting time; defoamers improve forming quality. Through 28 years of experience in mix proportion optimization, Qinglong Group has established scientific raw material selection standards, providing a solid foundation for the high performance of UHPC.