Characterization of toughness enhancement of aligned steel fibers in cement-based composites based on DDM method and meso-scale simulation

Abstract

In this study, the toughness enhancement of aligned steel fibers in cement-based composites was mainly characterized. Three-point bending fracture tests with different fiber orientations and fiber volume contents were performed; additionally, crack propagation processes of random and aligned steel fiber reinforced cement-based composites (SFRCs and ASFRCs, respectively) were investigated using the discontinuous deformation measurement (DDM) method. The evolution of the fiber stress and resultant fiber force F on the fracture surface was analyzed through a meso-scale simulation analysis. Results of the DDM method, reveal that compared with the SFRC, smaller strain concentration regions are observed for the ASFRC under the same load. A higher ultimate load and use efficiency of steel fibers are obtained for the ASFRC. Moreover, a higher maximum value of F is presented for the ASFRC; the same tendency is exhibited for F at the initial loading stage. Both these trends indicate that the aligned steel fibers improve the crack-resistance ability and result in a better toughness enhancement effect for the ASFRC than that of the SFRC.