Compressive behavior of partially encased recycled aggregate concrete columns after exposure to elevated temperature

• Published in: Journal of constructional steel research 2024-10, Vol.221, p.108889, Article 108889
• Main Authors: Liang, Jiongfeng, Wang, Liuhaoxiang, Zou, Wanjie, Li, Wei
• Format: Article
• Language: English
• Subjects: Eccentric compression; High temperature; Partially encased composite; Recycled aggregate concrete
• ISSN: 0143-974X
• DOI: 10.1016/j.jcsr.2024.108889

To explore the eccentric compressive behaviors of partially encased recycled aggregate concrete (PERAC) columns after exposure to high temperatures, 12 columns were tested in this paper, including 3 columns under axial load as controls. Factors considered in the experiment were replacement levels (r) of recycled coarse aggregate (RCA), temperature (T), and relative eccentricity (e/H). The test results show that the temperature rising of webs is effectively delayed by protection of recycled aggregate concrete (RAC). And the post-heated PREAC column has higher ductility under eccentric load due to the better deformation capacity of RAC than that of natural aggregate concrete (NAC). Similar to the effect of T, when the e/H adds from 0 to 0.2, both ultimate axial strength and initial stiffness of columns decrease significantly. When e/H adds from 0.2 to 0.4, flanges away from the loading axis are gradually changed from compression to tension. All columns eventually fail due to local buckling of flanges near loading axis. Compared with partially encased concrete (PEC) columns, the r of 50% is beneficial for PERAC columns to get better ductility and maintain stiffness. In addition, the modified method based on the code T-CECS719–2020 can be used to predict the ultimate strength of PERAC columns after exposure to high temperatures. •Compression tests are conducted on post-heated PERAC columns with different relative eccentricity.•Effects of different parameters on loading behaviors of PERAC columns were evaluated.•The presence of RAC can effectively delay the rise of web temperature during heating process of the column.•Columns exposed to higher temperatures tend to have larger deflection and lower loading capacity.•A bearing capacity calculation method for PERAC columns exposed to high temperatures is proposed.