Where Do UHPC Mix Ratio Differences Among Different Manufacturers Mainly Lie? Analysis of Mix Ratio Differences and Their Impact

The UHPC mix ratio is the core factor determining product performance, cost, and applicable scenarios. Due to differences in technical philosophy, equipment level, and raw material resources, mix ratio designs vary significantly among manufacturers. Clarifying the dimensions of mix ratio differences enables precise selection of products suited to project requirements. Drawing on its formulation R&D experience, Qinglong analyzes the core differences and their impacts.

I. Core Differences in Raw Material Selection and Dosage

Raw material selection and dosage form the basis of mix ratio differences. Cement type selection varies: some manufacturers use ordinary Portland cement, which has lower cost but slower strength development; high-end manufacturers such as Qinglong use low-alkali sulfoaluminate cement, offering high early strength and superior durability. Aggregate gradation differs significantly: quality manufacturers use continuously graded quartz sand (0.15-1.2mm) to improve density; some manufacturers have unreasonable aggregate gradation, causing large strength fluctuations. Steel fiber dosage and type differ: the conventional dosage is 2%-3%, and Qinglong uses 3% alkali-resistant steel fiber, while some manufacturers reduce the dosage to only 1.5%-2% to cut costs, resulting in a 15%-20% decrease in flexural strength; active admixture (silica fume, fly ash) dosages also vary: a silica fume dosage of 8%-10% can enhance strength, but some manufacturers use less than 5%, affecting densification.

II. Compatibility Differences in Water-Binder Ratio and Admixtures

The water-binder ratio and admixture selection directly affect UHPC performance. The water-binder ratio is a key indicator: quality UHPC controls it at 0.28-0.32, and Qinglong stabilizes it at 0.30 through high-range water reducers, ensuring strength and density; some manufacturers have a water-binder ratio above 0.35, which improves workability but reduces compressive strength by more than 10%. Admixture types and dosages differ: high-end manufacturers use polycarboxylate high-range water reducers at a dosage of 0.8%-1.2%, balancing dispersibility and slump retention; some manufacturers use ordinary water reducers, requiring increased dosages to achieve the effect, which easily leads to later-stage shrinkage cracking. Differences in the compatibility of auxiliary admixtures such as retarders and defoamers also affect workability and product quality.

III. Differentiated Design of Functional Mix Ratios

Mix ratio designs differ significantly to meet the functional requirements of different scenarios. Weather-resistant mix ratios: coastal high-salt-mist environments require the addition of corrosion inhibitors; in the Singapore National Defence Service Centre project, Qinglong added 2% corrosion inhibitor to improve corrosion resistance; some manufacturers make no targeted adjustments, easily leading to steel fiber corrosion. Lightweight mix ratios: lightweight aggregates such as ceramsite replace quartz sand, reducing bulk density to below 1800kg/m³, suitable for load-sensitive scenarios; conventional mix ratios have a bulk density of 2400-2500kg/m³, with higher strength but greater weight. Artistic decorative mix ratios: mineral pigments, light-transmitting materials, etc., are added; in the Shanghai New World Century Plaza project, Qinglong incorporated light-guiding materials into the mix ratio to achieve light-transmitting effects; ordinary mix ratios only meet basic performance requirements without special functions.

IV. Impact of Mix Ratio Differences on Product Performance and Cost

Mix ratio differences directly lead to divergence in product performance and cost. In terms of performance, UHPC produced with quality mix ratios achieves a compressive strength ≥120MPa and flexural strength ≥20MPa, with durability of over 20 years; low-cost mix ratio products reach only 100MPa in strength, with durability of less than 10 years. In terms of cost, the high dosage of quality raw materials such as steel fiber and silica fume results in higher mix ratio costs but lower whole-life-cycle costs; low-cost mix ratios require less initial investment but incur high later-stage repair and replacement costs. Selection should combine project performance requirements with budget, avoiding the blind pursuit of low prices. Qinglong provides customized mix ratio designs that balance performance and cost to suit different project requirements.