Title:
Model for Predicting the Elastic Strain of FRC Containing High Volume Fractions of Discontinuous Fibers
Author(s):
Prijatmadi Tjiptobroto and Will Hansen
Publication:
Materials Journal
Volume:
90
Issue:
2
Appears on pages(s):
134-142
Keywords:
discontinuous fibers; elastic properties; fiber reinforced concretes; high-strength concretes; concretes; modulus of elasticity; tensile strength; Materials Research
DOI:
10.14359/4007
Date:
3/1/1993
Abstract:
In this paper, a model is derived for predicting the increase in tensile strain capacity at first cracking of fiber reinforced composites (FRC) reinforced with high volume faction (i.e., typically 2 percent or higher) discontinuous fibers, randomly distributed throughout the matrix. The model is derived from energy principles, an approach similar to that used by Aveston, Cooper, and Kelly for continuous FRC. Due to the increased complexity in discontinuous FRC in obtaining the energy contribution from fibers and matrix to overall energy absorption at first cracking (i.e., elastic limit), the two models are quite different. The model predicts that the tensile strain capacity of a brittle cement-based matrix can be improved several times by the addition of high volume fraction (i.e., more than 2 percent) of fine and stiff fibers, provided that the matrix exhibits high bond strength. The proposed model was validated from a limited experimental program in which beans were made out of DSP (densified small particles) mortar containing 0, 3, 6, 9, and 12 percent of short (6-mm long) and fine (0.15-mm diameter) steel fibers tested in flexure. Results showed that the elastic strain capacity increased from 150 microstrain at 0 percent fiber content to 470 microstrain at 12 percent fiber volume fraction.