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 system. As a professional manufacturer with 28 years of deep industry experience, Qinglong UHPC systematically analyzes the raw material composition of UHPC and its key technical requirements based on extensive R&D achievements and engineering practice. A complete UHPC raw material system consists of five major categories: cementitious materials, aggregates, fibers, chemical admixtures, and mineral admixtures. The selection of each material directly affects the final product performance.

In the Shenzhen Yirui Biotechnology Building project, the raw materials used by Qinglong UHPC were rigorously selected: Grade 52.5 low-alkali cement ensures alkali content is controlled below 0.6%; silica fume has a SiO₂ content exceeding 92% with an average particle size of 0.1-0.2μm; quartz sand adopts continuous gradation with a maximum particle size of 0.6mm and a fineness modulus of 1.8-2.2; steel fibers are 13mm long with an aspect ratio of 65 and a tensile strength of 2800MPa; polycarboxylate superplasticizer achieves a water reduction rate exceeding 35%. This precise proportioning enables the product to reach a compressive strength of 140MPa and a flexural strength of 25MPa, far exceeding ordinary concrete performance indicators.

In-Depth Analysis of the Cementitious Material System

Cement is the core cementitious material of UHPC; low-alkali cement of Grade 52.5 or above must be selected, with alkali content controlled below 0.6%. As a key active admixture, silica fume requires a SiO₂ content greater than 92% and a specific surface area of 15,000-25,000m²/kg, enabling it to effectively fill micropores. Supplementary cementitious materials such as slag powder and fly ash can improve workability, but their dosage must be strictly controlled. The cementitious material optimization system established by Qinglong through 28 years of practice ensures that materials work synergistically, fully leveraging the composite cementitious effect.

Precise Proportioning of the Aggregate System

The maximum particle size of aggregates is typically controlled at 0.6-1.0mm, using continuous gradation design to achieve the densest packing. Quartz sand requires a SiO₂ content exceeding 99% with mud content below 0.2%. The gradation curve is optimized through the Andreasen model to maximize packing density. Qinglong's aggregate pretreatment process, including washing, sieving, and drying, ensures stable aggregate quality, which is the foundation for achieving high UHPC performance.

Selection of Fiber Reinforcement Materials

Steel fibers are the primary reinforcement material, typically 6-13mm in length and 0.15-0.20mm in diameter, with an aspect ratio of 60-80. Hooked-end steel fibers improve bonding strength, with a dosage generally of 2-3%. Under special requirements, polypropylene fibers can be blended in to improve crack resistance. Through optimized combinations of fiber types, dimensions, and dosages, Qinglong achieves precise control of material toughness.

Precise Control of Chemical Admixtures

Polycarboxylate superplasticizer is an essential component, requiring a water reduction rate exceeding 30% and good slump retention performance. Defoamers are added when necessary to control air content, and thickeners to improve viscosity. Qinglong's independently developed specialized admixture system can precisely control rheological properties to meet the requirements of different construction processes.

Raw material selection is the foundation of UHPC performance. It is recommended to choose manufacturers with a comprehensive raw material control system to ensure stable product performance. With 28 years of accumulated material research, Qinglong UHPC provides customers with optimal material solutions.