SBIR-STTR Award

Dowel bars have traditionally been used as an important load transfer mechanism on our federal highways. A significant problem occurs with the use of these bars due to rust and resultant spalling and cracking concrete. Composite Reinforcing Bars (CRB)have become widely used for crack control in many reinforced concrete structures exposed to aggressive environments. A limited amount of data is available regarding the characteristics and performance of this material. More information is necessary to fully understand CRB technology and to determine the feasibility of producing larger diameter bar material of this nature to successfully use as dowel bars at pavement joints on our highways. This proposal intends to analyze current CRB technology and determine the feasibility of producing larger diameter composite reinforcing bars that can be used as Fiber Composite Dowel bars using CRB technology The goal is to produce Fiber Composite Dowel bars of comparable shear and fatigue strength of currently used steel dowel bars being utilized in federal highway pavement design.Anticipated Results/Potential Commercial Applications Of Results:Anticipated Results-manufacture of FCD bars greater than 1" in diameter which will serve as replacement of current steel dowel bars. Commercial Application-New bar for use in pavements, joints and reinforced structures.

Perform a study and evaluation of large diameter noncorrosive fiber reinforced dowel bars for use as an alternative to steel dowels in highway pavement construction. The study includes a modification of an existing manufacturing process to produce larger diameter (1 1/2' smooth) bars from that currently produced ( 1 1/8' deformed). Long term dynamic cyclic loading of up to 20 mimon cycles will be performed on short dowelled shear beam test slabs. Static testing will also be performed on test slabs and individual components to develop strength and stiffness characteristics. In addition to the short beam tests, the research will include laboratory testing on long dowelled beams on an elastic foundation using a synchro@d dual ram test set-up to simulate field conditions. A University study will be conducted by the authors of PFALJLT to evaluate the impact of the effect of Dowel stiffness on the performance of FCD dowel/joint systems. A field test evaluation program will also be performed with a study on 12 in-service concrete pavement sections located in two separate climate zones. Each section will be subjected to a condition survey, Falling Weight Deflectmeter (@) testing and physical inspection and faulting evaluation on a periodic basis throughout the research period. Anticipated Results/Potential Commercial Applications of Results:To provide an economical alternative to steel dowel bars in highway pavement joints. The new FCD dowel bar will be noncorrosive, have extended service life and perform superior to steel dowels resulting in a savings t? tPg vaintenayse the Interstate ]Ji§@yay System.