Abrasion resistance and nanoscratch behavior of an ultra-high performance concrete

Premature deterioration of concrete due to abrasion has been a critical problem in many civil engineering structures. As a novel material, ultra-high performance concrete (UHPC) shows the potential to be used as an outstanding wear resistant material whereas there is a lack of detailed research on its abrasion behavior. This study investigated the abrasion resistance of a UHPC as compared with a high performance concrete (HPC), and nanoscratch tests were carried out to understand the underlying mechanisms that govern the macrobehavior. The results indicate that the abrasion resistance of the UHPC is approximately 50% higher than that of the HPC, which is primarily the result of the higher wear resistance of the UHPC paste. The scratch test results reveal that phases with higher hardness/stiffness such as unreacted particles are much less prone to be rubbed away than low hardness/stiffness phases like hydration products. Therefore, the UHPC paste, which is primarily comprised of high-stiffness hydration gels and unreacted particles, exhibits a higher scratch resistance than the HPC paste in terms of a smaller average scratch depth.