Abstract:
The main objective of this study was to investigate the effect of fiber volume (i.e
control, 0.5%, 1.0%, and 1.5%) and aspect ratios of 55, 65, and 80 of hooked-end steel fibers on the
behaviour of plastic shrinkage cracking during the first few hours after mixing. Properties such as
compressive strength, splitting tensile strength, VeBe time and wet density were investigated. During
this research two different strength levels (56 and 73 MPa at 28 days) were studied. The following
relations are obtained (a) Plastic shrinkage versus fiber volume, (b) Plastic shrinkage versus fiber
aspect ratio, (c) Plastic shrinkage versus strength level. The results indicated that the total plastic
shrinkage crack area and maximum plastic shrinkage crack width are significantly reduced with the
addition of steel fibers. Fiber content of 1.5% with aspect ratio of 80 resulted in a 74% and 70%
reduction in total crack area and maximum crack width, respectively compared to plain concrete
without fiber.
