MPC Research Reports
Report Details

Title:	Cracking and Debonding of Thin Fiber Reinforced Concrete Overlay
Authors:	Min Ook Kim and Amanda Christine Bordelon
University:	University of Utah
Publication Date:	Apr 2017
Report #:	MPC-17-319
Project #:	MPC-419
TRID #:	01635062
Keywords:	concrete overlays, cracking, debonding, fiber reinforced concrete, fracture mechanics, strength of materials

Abstract

Previous field studies suggested that macro-fibers incorporated in thin overlay pavements will result in reduced crack opening widths, vertical deflections, and debonding rates compared to that of unreinforced overlays. A simple finite element (FE) model was developed and utilized in this study to investigate how fracture energy can affect the cracking and debonding of thin concrete overlays subjected to environmental loads. It was confirmed that crack opening width, vertical lift-off, and debonding rate all decrease as the fracture energy across a joint increases or as the interfacial tensile bond increases. The developed FE model also used to make a comparison between fiber-reinforcement and dowel-bar reinforcement across a joint. With larger amounts of reinforcement across the joint, either by higher fiber contents or by larger diameter dowels, the crack opening width, vertical lift-off and debonding rates were all reduced. Experimental tests were carried out to measure the tensile and shear bond strengths of an interface between an aged concrete and a newly cast fiber reinforced mortar overlay. It was found that the tensile interfacial energy increased with fiber-reinforcement; however, the interfacial fracture occurred through the overlay mixture and was proportional to the number of fibers which intersected the fracture path near this interface. It was confirmed that no statistical trend could be found between the tensile or shear bond properties and the addition of fibers. Overall, a reduction in debonding exhibited in the field was explained because the fiber-reinforcement reduced curling-induced lift-off, according to the finite element results.

How to Cite

Kim, Min Ook, and Amanda Christine Bordelon. Cracking and Debonding of Thin Fiber Reinforced Concrete Overlay, MPC-17-319. North Dakota State University - Upper Great Plains Transportation Institute, Fargo: Mountain-Plains Consortium, 2017.