Effects of Holes and the Confining Pressure on the Mechanical Properties of High-Performance Concrete

Holes are often retained in concrete for holding cables and other industrial components. To ensure the safe application of high-performance concrete (HPC) members in a state of three-dimensional compression, research on the effects of holes on the mechanical properties of HPC members under triaxial compression is important. However, the triaxial compressive mechanical properties of HPC members with holes have not been studied. In this work, HPC specimens containing holes were experimentally studied under triaxial compression. The stress‒strain curves, strength, and failure mechanisms of HPC were obtained. The experimental results showed that both the confining pressure and the hole size influenced the mechanical properties of HPC. Moreover, the power-law failure criterion was modified to elucidate the relationship between the triaxial compressive strength of HPC and the hole size. In addition, the stress averaging method was first introduced to predict sidewall failure of a hole in concrete, and the experimental results were considered to modify the stress averaging method. The results indicated that the modified method can be used to accurately predict sidewall failure of holes and that both a decrease in the confining pressure and an increase in the hole size are conducive to hole failure. This study bridges the gap in research on HPC members with holes under triaxial compression, and provides an effective method to predict hole failure.