Direct shear performance and toughness evaluation of aligned steel fiber reactive powder concrete

To investigate the effects of steel fiber length, volume fraction, and distribution characteristics on the shear performance of reactive powder concrete (RPC) specimens under quasi-static loads, an electromagnetic field orientation device was used to orient the steel fibers in RPC. Three fiber volume fractions ( V_\mathrmf =1.0%, 1.5%, 2%) and three fiber lengths ( L_\mathrmf =13mm, 16mm, 20mm) were considered to produce aligned steel fiber reactive powder concrete (ASFRPC) specimens and randomly distributed steel fiber reinforced reactive powder concrete (SFRPC) specimens, and double-sided direct shear tests were conducted. The influence of fiber direction, fiber volume fraction, and fiber length on the shear strength, peak shear deformation, and shear toughness of all specimens were analyzed. The results show that the shear strength, shear deformation capacity, and shear toughness of ASFRPC specimens are significantly improved compared to SFRPC specimens. Steel fiber can significantly improve the direct shear mechanical properties of specimens after being oriented and distributed by a magnetic field.