PLASTIC SHRINKAGE CRACKING OF FIBER REINFORCED CONCRETE

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.