Title:
Fatigue Characteristics of Fiber Reinforced Concrete for Pavement Applications
Author(s):
V. S. Gopalaratnam and T. Cherian
Publication:
Symposium Paper
Volume:
206
Issue:
Appears on pages(s):
91-108
Keywords:
fatigue loading, fiber reinforced concrete, pavements, polymeric fibers, steel fibers, testing
DOI:
10.14359/12247
Date:
4/1/2002
Abstract:
Results from flexural fatigue tests on plain concrete and two fiber reinforced concrete (FRC) mixes (hooked-end steel fiber and polyolefin fiber) are presented and discussed. The specimens were made using the same concrete materials used for the MoDOT field test program. MoDOT's RDT Division was responsible for field implementation, which included design and construction of unbonded fiber-concrete overlays in the southbound lanes of Interstate 29 in Atchison County, Missouri, beween Route A and US 136. The fatigue performance of both the FRC mixes investigated in this study were superior to that5 of the Control mix. Crack widths in the Steel Fiber Reinforced Concrete (SFRC) specimens were typically smaller than those in the Polyolefin Fiber Reinforced Concrete (PFRC) specimens under comparable levels of fatigue loading (stress level as well as number of fatigue cycles). This property influences the long-term durability of the material for pavement applications. The difference between the FRC mixes and the Control mix becomes readily apparent at the higher levels of upper limit of fatigue stress. Fatigue failure in FRC can be characterized by a three-stage process. Iin the fist stage fatigue damage is accumulated in the concrete matrix. Rapid growth in net-deflection occurs with increasing fatigue cycles. The second stage is characterized gy little or no growth in net-deflections, attributable to stable and steady growth of damage along fiber-matrix interfaces. Only when this damage reaches a threshold level does the third stage begin. The third stage is characterized by a rapid growth in net-deflections resulting in fiber-pull out and /or fractures at the critical cross-section and associated catastrophic growth of the main matrix crack.