The mechanical characteristics of recycled large aggregate concrete show poorer performance than that of Portland-cement concrete due to the internal defects of recycled large aggregate (RLA). To improve the mechanical characteristics of recycled large particle size aggregate concrete, the recycled large aggregate Self-Compacting Concrete filled steel tube (RLA-SCCFST) is proposed. The external steel tube can not only keep the core recycled large aggregate concrete in the three-dimensional state of stress, but also prevent the crack expansion of the core recycled large aggregate concrete. RLA-SCCFST subjected to compression is studied experimentally. The compression failure tests use 20 specimens of circular section short column with different steel content rate, particle size of RLA, strength of RLA, strength of SCC, and eccentricity of the load. The influence of different factors on mechanical characteristics of RLA-SCCFST short cylindrical components subjected to compression is analyzed. The results indicate that the load-bearing performance of RLA-SCCFST short columns increases following with the augmentation of RLA particle size, strength of RLA particle size, strength of SCC and steel content rate. The load-bearing performance of RLA-SCCFST short columns reduced with the augmentation of the load eccentricity. And the experimental results are in high coincidence with those calculated by different formulas.

Based on the rapid carbonization test process of concrete, this paper studies and analyzes the influence of water-cement ratio, recycled aggregate content, fiber length and fiber content on the carbonation rule change of waste fiber recycled concrete. The results show that the depth of carbonization increases with the increase of water-cement ratio. With the increase of the replacement rate of recycled aggregate, the carbonation depth increases. The carbonation depth decreases with the increase of fiber length. As the proportion of waste fiber content increases, the carbonation depth does not change monotonously. The best content is 0.12%.