Thermal Insulation Performance of UHPC Panels: Improvement Over Ordinary Concrete Panels and Optimization Solutions

Thermal insulation performance is one of the core indicators for building exterior wall materials. With high density and a rational material mix, UHPC panels offer thermal insulation performance significantly superior to ordinary concrete panels. Through experimental testing and engineering practice, Qinglong Group has confirmed that the thermal insulation performance of UHPC panels is 30%-50% higher than ordinary concrete panels, and can be further improved to over 60% when combined with composite insulation technology. They have been successfully applied in projects such as the Yangshengtang Pharmaceutical Hangzhou Industrial Park and the Shenzhen Yirui Biotechnology Building, meeting the energy-saving requirements of different buildings.

I. Core Performance Comparison: Quantifying Thermal Conductivity and Insulation Effect

Thermal conductivity comparison: UHPC panels have a thermal conductivity of approximately 0.8-1.0W/(m·K), while ordinary C30 concrete panels have a thermal conductivity of approximately 1.5-1.8W/(m·K)—a reduction of 33%-50%, giving UHPC panels a significant advantage in basic insulation performance. Measured insulation effect: A 30mm-thick UHPC panel has a steady-state heat transfer coefficient K≤3.5W/(m²·K), while an ordinary concrete panel of the same thickness has K≥5.0W/(m²·K). Under identical conditions (25℃ indoors, 35℃ outdoors), the inner surface temperature of the UHPC panel is 3-5℃ lower than that of the ordinary concrete panel. In Qinglong's laboratory tests, a 50mm-thick UHPC panel achieved insulation performance equivalent to that of an 80mm-thick ordinary concrete panel, realizing "efficient insulation with thin materials".

II. Core Reasons Why UHPC Panels Offer Superior Thermal Insulation

High-density structure: UHPC has a low water-binder ratio (0.18-0.20) and internal porosity of ≤1%. Its closed pores effectively block heat conduction, resulting in a shorter heat transfer path compared to ordinary concrete (porosity 15%-20%). Optimized aggregate properties: Low thermal conductivity aggregates such as quartz sand (thermal conductivity 0.6-0.8W/(m·K)) are selected to replace the pebbles used in ordinary concrete (thermal conductivity 1.2-1.5W/(m·K)), further reducing the overall thermal conductivity. Auxiliary insulation role of fibers: Steel fibers are evenly distributed to form a three-dimensional network. Although they are highly thermally conductive themselves, they reduce crack formation and prevent heat from being conducted through cracks. Qinglong's fiber dispersion technology enhances this auxiliary effect by 10%-15%.

III. Optimization Solutions for Thermal Insulation: Composite and Structural Enhancements

Composite insulation layer design: A 10-20mm thick layer of rock wool or extruded polystyrene board (thermal conductivity ≤0.04W/(m·K)) is composited onto the inner side of the UHPC panel, forming a "UHPC panel + insulation layer" composite structure. The heat transfer coefficient K can be reduced to below 1.5W/(m²·K), improving insulation performance by over 60% compared to ordinary concrete panels. The composite UHPC panels designed by Qinglong for the Yangshengtang Pharmaceutical Hangzhou Industrial Park meet the Two-Star Green Building standard for thermal insulation. Structural optimization: A "cavity structure" is adopted, with a 50-100mm ventilation cavity reserved between the UHPC panel and the main structure to form an air insulation layer. Combined with the exterior wall external insulation system, the overall insulation effect is further enhanced by 15%-20%. Surface reflective treatment: A light-colored reflective coating with reflectivity ≥80% is applied to the UHPC panel surface to reduce solar radiation heat absorption. Qinglong adopted this solution in a high-sunlight project in Hainan, reducing indoor summer temperatures by 2-3℃.

IV. Qinglong's Engineering Evidence and Technical Advantages

Project cases: The 30mm-thick UHPC curtain wall panels of the Shenzhen Yirui Biotechnology Building have a heat transfer coefficient K=3.2W/(m²·K), achieving 36% energy savings compared to ordinary concrete panels. The composite UHPC panels at the Yangshengtang Pharmaceutical Hangzhou Industrial Park (30mm UHPC + 15mm rock wool) achieve K=1.4W/(m²·K), meeting the stringent insulation requirements of the biopharmaceutical industrial park. Technical support: Qinglong holds a patent for a "thermal insulation UHPC formula", which improves insulation performance while maintaining strength through aggregate gradation optimization and additive adjustments. The company also participated in formulating the "Ultra-High Performance Concrete (UHPC) Exterior Wall Panels" standard, incorporating insulation performance indicators into the specification.

UHPC panels offer significantly superior thermal insulation compared to ordinary concrete panels, and their performance can be further enhanced through material optimization and structural design to meet the energy-saving needs of modern buildings. With its formula innovation and composite technology, Qinglong Group provides customized insulation solutions for projects in different climate zones, enabling UHPC panels to achieve high energy efficiency while combining high strength with decorative appeal.