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摘要
To promote the utilization of excavated soil and waste concrete in building structures, recycled lump / aggregate concrete (RLAC) specimens were prepared by using demolished concrete lumps (DCLs), recycled coarse aggregates (RCAs), and weathered residual soil of granite (WRSG) after treatment. Uniaxial compression tests of 129 such specimens at room temperature and after high temperatures were carried out. Influences of the recycled materials, the shape and size of the specimens and the characteristic dimensions of DCLs on the compressive behaviors of specimens at room temperature were discussed. Effects of the exposure temperatures and the recycled materials on the residual compressive properties of the specimens were analyzed. Experimental results show that: when the total amount of water in the mix proportion of the new concrete keeps unchanged, in comparison with the conventional concrete without any recycled materials, the compressive strength of RLAC at room temperature increases with both the using of RCAs (less than 50%) and the increasing of the replacement ratio of the treated WRSG (less than 70%) in the new concrete, meanwhile the elastic modulus of RLAC decreases slightly and the Poisson’ s ratio of RLAC changes little. When the lateral dimensions of the specimens are in the range of 150 mm to 300 mm, the size effect of the compressive strength of RLAC at room temperature can be ignored approximately. When the characteristic ratio of DCLs ranges from 0. 22 to 0. 55, the influences of the size of DCLs on the compressive strength, elastic modulus, peak strain and Poisson’ s ratio of RLAC at room temperature can be neglected. Compared with conventional concrete without any recycled materials, the changes in the relative compressive strength and relative elastic modulus of RLAC after elevated temperatures are generally limited, and the proposed formulas can be used to predict the two relative quantities well. ? 2023 Science Press.
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