Where Do UHPC Mix Proportions Differ Among Manufacturers? Formulation Secrets and the Performance-Oriented Microscopic World

The differences in mix proportions among different UHPC manufacturers are a concentrated reflection of their technical depth, cost strategies, and performance priorities, ultimately determining the product's performance ceiling and cost structure. Qinglong Group possesses a core formulation system optimized through 28 years of iteration. In our view, the differences mainly focus on three major aspects: the selection and optimization of the "cementitious material system", the "composition of the fiber reinforcement system", and the "types and compounding of core functional admixtures"—together these shape the strength, toughness, durability, and workability of UHPC.

In terms of the cementitious material system, the differences are significant. First is the choice of cement type and grade (e.g., 52.5 ordinary Portland cement, 52.5 white cement, or sulphoaluminate cement), which directly affects the matrix color, early strength, and alkalinity. Next is the type and dosage of active supplementary cementitious materials, such as the compounding ratios of silica fume, slag powder, and fly ash. A high silica fume content (e.g., 20-30%) can greatly improve density and early strength, but cost and autogenous shrinkage will also increase. Through extensive research, Qinglong Group has found the optimal balance between strength development and volume stability. Finally, there is the water-binder ratio, one of the most critical parameters affecting strength; premium UHPC can achieve a ratio as low as below 0.18, but this places extremely high demands on water reducers and mixing processes.

In terms of the fiber reinforcement system, the choices and combinations are diverse. Should steel fibers, synthetic fibers (e.g., PVA, PP), or a combination of both be used? What are the diameter, length, aspect ratio, end shape (e.g., straight, hooked), and volume dosage (typically 2-3%) of the steel fibers? Synthetic fibers are mainly used to control early plastic cracking. Based on their product positioning (e.g., ultra-high-strength, high-toughness, or economy type) and process adaptability, different manufacturers adopt vastly different fiber solutions. Qinglong Group has developed multiple fiber reinforcement solutions in reserve for different application scenarios.

In terms of the admixture system, this is the "core technology" of the formulation. High-efficiency polycarboxylate superplasticizers are the foundation, but their molecular structure design and compounding techniques (e.g., compounding with retarders, defoamers, and viscosity modifiers) vary greatly, directly affecting the rheology, homogeneity, and workable time of the slurry. In addition, whether special functional admixtures are added—such as internal curing agents, shrinkage-reducing agents, and anti-rust agents—also reflects the manufacturer's technical depth. In short, the UHPC mix proportion is a complex systems engineering endeavor, and its differences directly result in different performance "genes" of the products. When making a choice, customers should require manufacturers to clearly state the performance orientation of their formulations, and ideally verify it through samples and test reports.