Assessment of fiber distribution characteristics in the hybrid fiber reinforced concrete – An experimental study

Abstract

Assessment of fiber distribution characteristics is critical in the determination of the mechanical properties of the Fiber Reinforced Concrete (FRC). In this study an experimental investigation was carried out to ascertain the Fiber distribution characteristics (Fiber dispersion coefficient and Fiber orientation factor) of the M30 grade Mono Glass FRC (MGFRC), Mono Steel FRC (MSFRC), Graded FRC (GrFRC), Hybrid FRC (HyFRC) and Hybrid Graded FRC (HyGrFRC). Two lengths of glass fibers and two lengths of steel fibers were blended into the concrete to obtain MGFRC, MSFRC, GrFRC, HyFRC, and HyGrFRC mixes. An image analysis technique using an optical microscope was used to determine the dispersion coefficient and orientation factor of all the mixes, as mentioned earlier. Effect of fiber length, fiber type and fiber grading on the fiber distribution characteristics of the FRC mixes were discussed. The fiber distribution characteristics were improved by the addition of glass and steel fibers, where glass fibers enhance the dispersion coefficient, and steel fibers enhance the orientation factor. Graded FRC specimens exhibited better fiber distribution than Mono FRC specimens. HyGrFRC specimens showed better fiber distribution characteristics when compared to HyFRC specimens, and this may be due to the more uniform distribution of fibers without clumping in HyGrFRC mixes due to the grading of fibers. From this study, it can be inferred that the blending of graded glass and graded steel fibers in a hybrid form into the concrete have shown a remarkable enhancement in the fiber distribution characteristics.