Accelerated Loading Testing of Stainless Steel Hollow Tube Dowels

Abstract

The use of dowels in rigid pavements to provide adequate load transfer is a common practice in current pavement design. Since the use of deicing 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. Results are presented 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 was accomplished courtesy of the second generation of the Minnesota Accelerated Loading Facility (MinneALF-2), a 10-year-old joint project between the Minnesota Department of Transportation 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 with linear variable differential transformers, 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 that for the epoxy-coated dowels, the results suggest that the stainless steel tubes are capable of providing a sufficiently high long-term LTE for concrete pavement joints. At the same time, the stainless steel hollow tube dowels considerably reduce the risk of joint deterioration due to dowel corrosion.