Title: Influence of Different Fibers on Plastic Shrinkage Cracking of Concrete

Author(s): Antoine E. Naaman, Thanasak Wongtanakitcharoen, and Gabriel Hauser

Publication: Materials Journal

Volume: 102

Issue: 1

Appears on pages(s): 49-58

Keywords: plastic shrinkage cracks; polyethylene; polyvinyl acetate; restraint of concrete

DOI: 10.14359/14249

Date: 1/1/2005

Abstract:
The main objective of this study was to evaluate the effect of a number of fibers, which covers a wide range of properties, on the plastic shrinkage cracking characteristics of concrete during the first 24 h after mixing. Four synthetic fibers—polypropylene, polyvinyl acetate (PVA), high-density polyethylene (HDPE), and carbon—as well as flexible metallic fibers (FMF), were investigated at volume fractions varied from 0.05 to 0.4%. Testing parameters cover a wide range of fiber properties including diameter, length, cross section, form, bond strength, and elastic modulus. Prismatic concrete specimens (1016 x 76.2 x 38.1 mm) freshly cast on top of a grooved and hard concrete substrate were investigated under adverse environmental conditions, namely, high temperature, low relative humidity, and high volume and velocity of airflow. The experimental results indicated that the volume fraction and diameter of fiber reinforcement are the two most influential parameters in controlling plastic shrinkage cracking of concrete. For a given volume fraction of fibers, changing the fiber length or aspect ratio did not have a noticeable effect on plastic shrinkage cracking. On the other hand, decreasing the fiber diameter or equivalently increasing the number of fibers crossing a unit area significantly improves the control of plastic shrinkage cracking. At a volume fraction of 0.2%, most fine-diameter fibers tested provided a reasonable control of plastic shrinkage cracking, reducing it to approximately 10% of control.