## 5 Conclusions  
1. For the concrete specimens, as the corrosion rate increased, corrosion cracks in the concrete began at the bottom and gradually developed upwards. Specimen N3 exhibited longitudinal cracks through the material, with corrosion products continuously precipitating on the surface, extending from the bottom to the top along the cracks. In contrast, the corrosion phenomena in UHPC were less pronounced. In the early stages of corrosion, only a few point-like corrosion products appeared on one side of the UHPC specimens. Starting with specimen U4, corrosion cracks and spalling began on the side with more corrosion products, with an increase in the corrosion products. As corrosion progressed, spalling eventually occurred at the bottom of the UHPC specimens.
2. Starting from N3, the concrete short columns showed noticeable uneven corrosion of the reinforcing steel, whereas the UHPC short columns exhibited uniform corrosion throughout the entire process. Due to the earlier cracking of the concrete specimens, the corrosion rate of their reinforcing steel remained relatively stable, around 70% of the theoretical value. In contrast, the UHPC specimens performed better throughout the corrosion process, with the corrosion rate displaying two distinct phases. The overall actual corrosion rate of the UHPC reinforcing steel was around 40% of the theoretical value.
3. From the experimental observations, it is evident that the corrosion rates of both concrete and UHPC short columns after accelerated corrosion are significantly lower than the theoretical corrosion rates. This discrepancy has also been noted in pre  
Figure 11: The fitted linear corrosion rate curves for the concrete and UHPC short columns: (**a**) the fitted corrosion rate curve for the NC specimens and (**b**) the fitted corrosion rate curve for the UHPC specimens.  
vious research. The theoretical corrosion rates calculated based on [PERSON]'s law do not adequately account for factors such as chloride ion concentration and cover thickness. Therefore, it is suggested that future studies focus on this area to develop a more realistic corrosion rate calculation equation that better reflects actual engineering conditions.
* This study compared the corrosion phenomena and patterns of ordinary concrete and UHPC specimens. This research allowed us to investigate the corrosion behavior of different material components in actual structures on a smaller scale and at a lower cost. Future research can build on this study to further explore the bond strength of internal steel reinforcements after corrosion and the seismic performance of both materials post corrosion.  
Conceptualization, T.T.; methodology, X.W.; software, H.W.; validation, H.W.; formal analysis, H.W.; investigation, H.W., J.H. and X.W.; resources, T.T.; data curation, H.W.; writing--original draft preparation, H.W.; writing--review and editing, H.W.; visualization, H.W.; supervision, T.T. and X.W.; project administration, T.T.; and funding acquisition, T.T. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
The authors declare no conflicts of interest.