Biaxial Behavior of Steel Fiber–Reinforced Recycled-Aggregate Concrete Subjected to Dynamic Compression: Fid-Bau Portal

Biaxial Behavior of Steel Fiber–Reinforced Recycled-Aggregate Concrete Subjected to Dynamic Compression

Li, Ping / Liu, Zhenzhen / Lin, Chenlong / Li, Shan / Lu, Yiyan

This paper presented an experimental study on the dynamic biaxial mechanical behavior of steel fiber-reinforced recycled-aggregate concrete (SFRRAC) samples. Five control variables, including lateral pressure ( $σ_{2}$ ), strain rates ( $\dot{ε}$ ), volume content of steel fibers ( $V_{s f}$ ), volume content of polyvinyl-alcohol fibers ( $V_{p f}$ ), and substitution ratio of recycled coarse aggregate (SRCA) were designed. Under different values of $σ_{2}$ , two distinct failure modes of samples were observed: columnar failure and oblique shear failure. However, the failure modes showed no substantial differences at various values of $\dot{ε}$ , $V_{s f}$ , $V_{p f}$ , and SRCA. The results indicated that the biaxial strength exhibited a general trend of initially increasing and then decreasing with increasing $σ_{2}$ . Specially, the biaxial strength exhibited a maximum increase of approximately 67% when $σ_{2}$ reached 40 MPa. The lateral pressure was more significant than the strain rate in terms of material strengthening. The dynamic biaxial strength exhibited a linear correlation with the logarithm of the strain rate. The incorporation of steel fibers and polyvinyl-alcohol (PVA) fibers resulted in a slight 9.3% improvement in biaxial strength but significantly improved its deformation capacity. To achieve maximum strength, the optimal values of $V_{s f}$ and $V_{p f}$ were found to be 1.2% and 0.1%, respectively. With SRCA increasing from 0% to 100%, the biaxial strength decreased by approximately 11%. Moreover, this paper proposed two dynamic failure criteria, one in the principal and the other in the octahedral stress spaces. These criteria exhibited good agreement with the experimental data.