What Special Designs Are Required to Achieve the Fire Resistance of UHPC?

Enhancing UHPC's fire resistance requires a three-in-one special design of "material modification, structural design, and protective measures" to address risks such as matrix spalling, fiber softening, and sudden strength loss at high temperatures. Based on fire resistance experiments and project practice (such as the fire protection requirements of Huawei's Songshan Lake base), Qinglong Group has summarized key measures: incorporating 0.1-0.2% polypropylene fibers into the material (which melt at high temperatures to form pressure-relief channels), adopting a phosphate cement system (temperature resistance ≥1000°C), and adding nano silica (to improve residual strength at high temperatures); structurally, installing fire protection layers (such as thick fire-retardant coatings) and optimizing connector insulation; and performing fire resistance limit calculations during system design (target 1-2 hours). In a data center project in Shenzhen, by combining polypropylene fibers with aluminate cement, we enabled UHPC panels to retain ≥50% of their compressive strength at 800°C high temperatures without spalling. Fire-resistant design is an extended topic for the safe application of UHPC.

Material-Level Modification to Resist High-Temperature Degradation

Adding polypropylene fibers (melting point approximately 160°C) is the core anti-spalling measure; after melting, the fibers form micropores that release steam pressure. In Qinglong Group's formula, PP fibers are 6-12mm long with a dosage of 0.15% to ensure uniform distribution. Meanwhile, aluminate cement or mineral powder additions are used to reduce calcium hydroxide content, preventing decomposition shrinkage at high temperatures.

Structural Design to Block Heat Transfer

For load-bearing UHPC components, a 20-30mm thick fire protection layer (such as cement-based thick coatings) is applied to delay the time for the temperature to reach 500°C to more than 2 hours. Connectors are made of stainless steel and wrapped with insulating materials to avoid thermal bridging. Qinglong's BIM team simulates temperature fields in the design to optimize protection layer thickness.

System Verification to Ensure Overall Fire Resistance

Standard fire resistance tests (ISO 834) are used to verify the fire resistance limits of components. Qinglong Group cooperates with testing institutions to conduct actual tests on UHPC components for key projects, ensuring compliance with standards. In a commercial complex in Wuhan, the UHPC staircases we provided were tested to withstand fire for 1.5 hours, far exceeding ordinary concrete.

Through targeted design, UHPC can perform well in scenarios with fire protection requirements. Qinglong Group makes fire resistance a standard option for premium UHPC, expanding its application boundaries.