What Are UHPC's Biggest Performance Weaknesses?

Although UHPC possesses many outstanding properties, as a material supplier, Qinglong Group believes that objectively understanding its performance weaknesses is crucial for engineering applications. Through 28 years of engineering practice, we have found that UHPC mainly suffers from performance weaknesses such as pronounced brittleness, large shrinkage deformation, high temperature sensitivity, and relatively high cost, all of which require full attention in design and application.

Brittleness remains the main performance weakness of UHPC. Although its toughness is far superior to that of ordinary concrete, it is still brittle compared with metallic materials. When stress exceeds the ultimate strength, UHPC often undergoes sudden brittle failure without obvious warning signs. In the Shenzhen Yirui Biotechnology Building project, Qinglong Group addressed this weakness by adding early-warning devices and optimizing structural details. Test data show that the ultimate compressive strain of UHPC is approximately 0.003-0.004; although higher than that of ordinary concrete, it is still far below the 0.02+ of steel.

Shrinkage deformation is another significant weakness. Due to its low water-binder ratio and high binder content, both the autogenous shrinkage and drying shrinkage of UHPC are relatively large. Qinglong Group's monitoring data show that the 28-day autogenous shrinkage of UHPC can reach 500-800μm/m, which is 2-3 times that of ordinary concrete. In the Wuhan Hanxiu Theater project, we effectively controlled the occurrence of shrinkage cracks by optimizing the curing regime and setting shrinkage joints. This large shrinkage characteristic requires sufficient structural measures to be considered at the design stage.

Temperature sensitivity is a weakness of UHPC that is easily overlooked. Its coefficient of thermal expansion is approximately 10-12×10⁻⁶/℃, which is comparable to that of ordinary concrete, but because of its high elastic modulus, the stress induced by temperature changes is greater. In the Shanghai Century Plaza project, Qinglong Group avoided damage caused by thermal stress by precisely calculating thermal deformation and installing flexible connections. In areas with intense sunlight, this weakness requires special attention.

The relatively high cost also limits the widespread application of UHPC. Its raw material cost is 5-10 times that of ordinary concrete, and its production process requirements are also higher. Qinglong Group has been striving to reduce costs through large-scale production and technological innovation, but at present UHPC is still mainly used in key projects with high performance requirements. Recognizing these performance weaknesses helps apply UHPC more scientifically, leveraging its advantages and avoiding its disadvantages.