Abstract
To explore the influence of microexpansive concrete self-stress on the performance of steel pipe concrete, the expansion rate test of microexpansive concrete confined by steel tube was carried out with different expansion rates. Then, the mechanical properties of high-strength steel tube-confined microexpansive concrete (HSTCMC) short columns were conducted by the uniaxial compression test. The length-to-diameter ratio, the expansion rate of the microexpansive concrete, and the steel tube thickness were investigated in the study. Furthermore, the ABAQUS software was employed to analyze the microexpansive mechanism of the concrete, and it was verified by the uniaxial compression test. The test results show that the concrete possesses a remarkable volume expansion phenomenon, which was up to 150 με after four days of maintenance time. The mechanical properties of the HSTCMC short columns were greatly improved compared to the control RC pier. The yield and ultimate strength of the HSTCMC short columns can be enhanced to 8.9% and 14.6%, and with the content of expansive agent that increased from 8% to 12%. The finite element analysis results highlighted that the end constraint at the two ends has the biggest influence on the mechanical performance of the HSTCMC short columns, followed by the thickness of the steel tube and the content of the expansive agent. It should be noted that the self-stress of microexpansive concrete will be decreased with the increase in the length-to-diameter ratio, when the length-to-diameter ratio is less than four. Furthermore, the constraint effect of the circular steel tube on the microexpansive concrete is better than that of the rectangular section steel tube.
Highlights
In recent years, long-span high-rise building structures are emerging, and as the main load-bearing component, the mechanical performance of the pier column is important
The hoop stress and axial stress produced by microexpansive concrete are less than those of the circular section. e reason is that the sidewall of the high-strength steel tube for the square cross section will deform together with the microexpansive concrete during the volume expansion process and completely confine the core concrete. at is, the constraint effect of the circular cross section is superior to that of the square cross section
The ABAQUS software was employed to analyze the microexpansive mechanism of the concrete, and it was verified by the uniaxial compression test; the following conclusions can be drawn: (1) e microexpansive concrete can greatly induce the shrinkage phenomenon of ordinary concrete, in which volume expansion can be up to 150 με after four days of maintenance time. e axial stress and hoop stress of the microexpansive concrete can be effectively enhanced by increasing the content of the expansive agent, and the hoop stress of the microexpansive concrete is relatively larger than the axial stress
Summary
Long-span high-rise building structures are emerging, and as the main load-bearing component, the mechanical performance of the pier column is important. Lu et al [12, 13] found that the initial self-stress can significantly improve the bearing capacity of the steel fiberreinforced microexpansive concrete short columns, the selfstress can significantly improve the bonding strength between the steel tube and concrete, and there is an optimal value of steel fiber content for improving the bond performance. He et al [14] found that when the hoop coefficient is small, the radial deformation of steel tube reduces the constraint effect of steel tube on microexpansive concrete, and the effect of improving the bearing capacity of members is not obvious. This study carried out the experimental study of five steel tubeconfined microexpansive concrete short columns and analyzed impactions that caused steel tube thickness, end constraint, expansion rate, section form, length-to-diameter ratio, and other parameters to the self-stress of microexpansive concrete, providing a reference for the application of steel tube-confined microexpansive concrete column in protection engineering
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
