INFLUENCE OF DIFFERENT FIBERS ON PLASTIC SHRINKAGE CRACKING OF CONCRETE

Plastic shrinkage cracks in concrete become critical weak points for aggressive substances to penetrate into the internal portion of concrete leading to the acceleration of concrete deterioration. Thus, controlling plastic shrinkage cracking (which usually occurs in the first few hours after the concrete is placed) is vital for developing more durable and longer-lasting structures at a minimum life-cycle cost. This article reports on a study undertaken to evaluate the effect of a number of fibers on the plastic shrinkage cracking characteristics of concrete during the first 24 h after mixing. The study included four synthetic fibers: polypropylene, polyvinyl acetate (PVA), high-density polyethylene (HDPE), and carbon, as well as flexible metallic fibers (FMF), at volume fractions varied from 0.05 to 0.4%. The research explored a range of fiber properties including diameter, length, cross section, form, bond strength, and elastic modulus. Prismatic concrete specimens 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 authors conclude that the volume fraction and diameter of fiber reinforcement are the two most influential parameters in controlling plastic shrinkage cracking of concrete. The addition of any fiber with a diameter smaller than 40 microns, with an aspect ratio above 200, in volume fractions in the range of 0.2 to 0.4% (or exceeding that) should, for all practical purposes, eliminate plastic shrinkage cracking in concrete.

Language

  • English

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00986588
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 28 2005 12:00AM