"This study evaluates fiber reinforced polymer (FRP) dowel bars as load transferring devices in jointed plain concrete pavement (JPCP) under HS25 static and fatigue loads and compares their response with JPCP consisting of steel dowels. Along with laboratory and field evaluations of JPCP with FRP and steel dowels, analytical modeling of dowel response was carried out in terms of maximum bending deflection, relative deflection (RD), and bearing stress of dowels. In addition, field rehabilitation of JPCP was carried out using FRP dowels to evaluate its long-term performance"--Technical report documentation page.

Dowel bars are used to transfer loads between adjacent pavement sections within a jointed concrete pavement. Epoxy coated steel is the most common material used for dowel bars, but steel dowel bars have been found to be susceptible to corrosion. The objectives of this research is to investigate fiber reinforced plastic (FRP) and stainless steel as alternative dowel bar materials, and to study the effects of FRP and stainless steel dowels size and spacing on load transfer behavior of concrete pavements. The load transfer behavior of the pavement was evaluated biannually by utilizing a falling weight deflectometer (FWD), measuring joint faulting and joint opening, and conducting a visual distress survey. The analyses indicate the epoxy coated steel outperformed the alternative materials. The average research lifetime load transfer for the epoxy coated steel is 91 percent, while the best performance of the alternative material at the same 12 inch on center spacing is approximately 87 percent for the stainless steel. The data also indicate the decrease in spacing, from 12 to 8 inches, increases the load transfer for stainless steel and 1.5 inch diameter FRP dowels. Although the FRP dowels with decreased spacing were outperformed by the epoxy coated steel dowels, they performed adequately. It is recommended that the current dowel bar standard continue to be implemented for concrete pavements requiring dowels as load transfer devices. However, if the pavement is to be constructed in a corrosive environment or a longer design life is desired, stainless steel spaced at 12 inches and 1.5 inch diameter FRP dowels spaced at 8 inches should be considered.

This TechBrief discusses the potential use of fiber-reinforced polymer (FRP) bars in continuously reinforced concrete pavements (CRCP). Relative advantages and disadvantages of FRP bars are presented, and some specific considerations for the use of FRP bars in CRCP design and construction are described. This is followed by an overview of two recent experimental CRCP projects that have been constructed with FRP bars.

The introduction of fiber reinforced plastic (FRP) dowels as possible alternatives to the epoxy-coated and stainless-steel dowels, was contemporaneous with a paucity of knowledge of their long-term performance. Although various isolated efforts had examined them on a short-term basis and produced some qualitative results or long-term predictive models, actual long-term performance in service was still unknown and unanalyzed. An experiment at the MnROAD Research facility placed FRP dowels in 2000 in some of the jointed plain concrete pavement (JPCP) panels of test Cell 52 and used epoxy-coated dowels in the remaining panels of this cell. The contiguity of this test cell with Cell 53, a JPCP high-performance concrete cell built in 2008 with stainless steel dowels, and Cell 54, a taconite JPCP cell with epoxy-coated dowels in built in 2004, facilitated a comparative analysis of performance of the 3 dowel types particularly in load transfer efficiency (LTE) and ride quality. The difference in the inception of the cells constrained a performance over time and encouraged a time-series autoregressive integrated moving average (ARIMA) analysis. Projections to 30 years showed that LTE and ride quality of FRP dowels were no different from those of the epoxy-coated dowels and the stainless-steel dowels although Cell 53 was designed and built with thicker concrete (12-in. thick) compared to 7.5-in in cells 52 and 54.

Transverse joints are placed in portland cement concrete pavements to control the development of random cracking due to stresses induced by moisture and thermal gradients and restrained slab movement. These joints are strengthened through the use of load transfer devices, typically dowel bars, designed to transfer load across the joint from one pavement slab to the next. Epoxy coated steel bars are the materials of choice at the present time, but have experienced some difficulties with resistance to corrosion from deicing salts. The research project investigated the use of alternative materials, dowel size and spacing to determine the benefits and limitations of each material. In this project two types of fiber composite materials, stainless steel solid dowels and epoxy coated dowels were tested for five years in side by side installation in a portion of U.S. 65 near Des Moines, Iowa, between 1997 and 2002. The work was directed at analyzing the load transfer characteristics of 8-in. vs. 12-in. spacing of the dowels and the alternative dowel materials, fiber composite (1.5- and 1.88-in. diameter) and stainless steel (1.5-in. diameter), compared to typical 1.5-in. diameter epoxy-coated steel dowels placed on 12-in. spacing. Data were collected biannually within each series of joints and variables in terms of load transfer in each lane (outer wheel path), visual distress, joint openings, and faulting in each wheel path. After five years of performance the following observations were made from the data collected. Each of the dowel materials is performing equally in terms of load transfer, joint movement and faulting. Stainless steel dowels are providing load transfer performance equal to or greater than epoxy-coated steel dowels at the end of five years. Fiber reinforced polymer (FRP) dowels of the sizes and materials tested should be spaced no greater than 8 in. apart to achieve comparable performance to epoxy coated dowels. No evidence of deterioration due to road salts was identified on any of the products tested. The relatively high cost of stainless steel solid and FRP dowels was a limitation at the time of this study conclusion. Work is continuing with the subject materials in laboratory studies to determine the proper shape, spacing, chemical composition and testing specification to make the FRP and stainless (clad or solid) dowels a viable alternative joint load transfer material for long lasting portland cement concrete pavements.