Comparative study on axial compressive properties of steel fiber-reinforced recycled-fine-aggregate concrete tested by prism and cylinder specimens

This paper compared the axial compressive properties of steel fiber-reinforced recycled-fine-aggregate concrete (SFRFAC) tested by prism and cylinder specimens. Compressive strength test, elastic modulus test and axial compressive stress–strain curve test were performed using the prism specimen of 150 mm × 150 mm × 300 mm and the cylinder specimen of Φ150 mm × 300 mm. The effects of recycled-fine-aggregate (RFA) replacement ratio, steel fiber volume fraction, steel fiber type and silica fume content on the axial compressive properties of SFRFAC were analyzed. Meanwhile, acoustic emission (AE) and digital image correlation (DIC) technique were used to pursue the failure process, the internal damage, and the surface crack development of SFRFAC specimen, respectively. The results show that the compressive strength and peak strain of SFRFAC prism specimen are smaller than those of cylinder specimen, while the elastic modulus and compression work of SFRFAC prism specimen are larger than those of cylinder specimen. Moreover, compressive strength, elastic modulus and compression work are decreased and the maximum decrease rates are 11.5 %, 14.4 % and 9.8 %, respectively, while peak strain is increased and the maximum increase rate is 7.1 % due to the addition of RFA. Compressive strength, elastic modulus, peak strain and compression work are increased and the maximum increase rates are 37.8 %, 5.1 %, 62.4 % and 158.2 %, respectively, due to the addition of steel fiber. Compressive strength, elastic modulus, peak strain and compression work are increased and the maximum increase rates are 10.9 %, 1.2 %, 8.4 % and 13.3 %, respectively, due to the addition of silica fume. Finally, the axial compressive stress–strain relationships of SFRFAC tested by prism specimen and cylinder specimen were compared and proposed, respectively.