Sulaiman, AlaaHunaiti, YasserAbdel-Jaber, Mu’tasimAbdel-Jaber, Ma’en2022-06-172022-06-172022-06-162062-0810http://hdl.handle.net/2437/335476The axial capacity of light–gauge steel tube columns filled with concrete including recycled asphalt pavement (RAP) aggregates and recycled concrete aggregates (RCA) was investigated. A total of 51 specimens, including 6 bare steel tubes, 30 composite columns and 15 concrete-only columns were tested under uniaxial load. Fifteen concrete mixes were considered by replacing the weight of natural coarse aggregates (NA) with RCA and RAP at replacement levels of 0, 20, 40, 60, 80, and 100%. In addition, RAP and RCA were combined in the same mixes with replacement levels of (1) 20% RAP and 80% RCA; (2) 40% RAP and 60% RCA; (3) 60% RAP and 40% RCA; and (4) 80% RAP and 20% RCA. Experimental results were analyzed by reporting the ultimate capacities and the patterns of failure. Moreover, the predictions of EUROCODE 4 (EC4) and American Institute of Steel Construction (AISC) codes were checked. ABAQUS software was used to perform a finite element analysis (FEA) of the tested composite specimens. The results showed that using recycled aggregates decreased the carrying capacity of columns. Carrying capacity of light–gauge steel tubes filled with concrete including different combinations of RCA, NA and RAP aggregates can be conservatively predicted by the AISC and EC4 recommendations. Results of FEA showed a good agreement with the experimental results.enaxial loadcomposite columnsrecycled asphalt pavement aggregatesrecycled concrete aggregatessteel tubehttps://akjournals.com/view/journals/1848/13/2/article-p185.xml10.1556/1848.2021.00333International Review of Applied Sciences and Engineering213