The use of dowels in rigid pavements to provide adequate load transfer is a common practice in current pavement design. As the use of de-icing salts in cold climates results in significant deterioration of dowels, the need to optimize performance and reduce pavement life cycle cost prompts the need for alternatives to common round steel dowel bars. These alternative dowels must be able to withstand corrosion while providing adequate long-term load transfer performance across jointed slabs. This paper presents the results of the accelerated loading of two jointed test pavement specimens that incorporate one of two types of dowels: a stainless steel hollow tube dowel or an epoxy-coated solid steel dowel. The accelerated loading of these test specimens is accomplished courtesy of the second generation of the Minnesota Accelerated Loading Facility (MinneALF-2), a ten year-old joint project between the Minnesota Department of Transportation (MnDOT) and the University of Minnesota that allows for the realistic simulation of repeated truck loading of concrete pavement joints. For this study, each specimen was subjected to 10 million 9-kip loading cycles. Deflections between jointed slabs were measured using LVDTs, and the load transfer efficiency (LTE) for each case was calculated from these measurements. Although the LTE for the stainless steel hollow tube dowels was lower than the LTE for the epoxy-coated dowels, the results suggest that the stainless steel tubes are capable of providing a sufficiently high long-term LTE (over 70%) for concrete pavement joints. Considering that the stainless steel hollow tube dowels considerably reduce the risk of joint deterioration due to dowel corrosion, they are an attractive alternative to the epoxy-coated dowels for use in long-life pavements.
Samenvatting