What Are UHPC's Biggest Performance Weaknesses?

Despite its many excellent properties, UHPC still has some technical shortcomings that need to be objectively recognized. These weaknesses are mainly concentrated in its material properties and application technologies.

In multiple engineering practices, Qinglong UHPC has shown the following aspects needing improvement: relatively low elastic modulus compared to steel (50GPa vs 200GPa), leading to insufficient stiffness; brittleness, though improved, still exists, and brittle failure may occur under impact loads; shrinkage deformation is relatively large, especially early shrinkage which needs effective control; and differences in thermal expansion coefficient from ordinary concrete may cause interface problems.

Elastic Modulus Limitation

The elastic modulus is approximately 45-55GPa, only 1/4 that of steel, and may become a constraining factor in stiffness-controlled designs.

Residual Brittleness Problem

Although reinforced with fibers, it is still essentially a brittle material, and sudden failure may occur under extreme loads.

Shrinkage Deformation Control

Autogenous shrinkage and drying shrinkage are relatively large, with totals reaching 800-1000μm/m, requiring compensatory measures.

Thermal Performance Characteristics

Differences in thermal expansion coefficient from ordinary concrete may cause thermal stress, which needs to be considered in design.

Recognizing these weaknesses helps to better apply UHPC, leveraging strengths and avoiding weaknesses through reasonable design and construction measures.