Chapter 22 - North American Overview and a Canadian Perspective on the Use of Tire-Derived Aggregate in Highway Embankment Construction

Abstract

Many projects using tire-derived aggregate (TDA) as a lightweight fill have been successfully completed in United States since 1990. In comparison, the use of TDA has been less prevalent in Canada, but its use is being considered increasingly in highway infrastructure projects. In this chapter, a review of TDA-related work in Canada is presented with the main emphasis being on a case study in which TDA was used to reconstruct a section of failed slope of a highway embankment in New Brunswick. The embankment failure occurred in 2006 during construction of a four-lane divided highway leading to the Canada–U.S. border crossing in St. Stephen, New Brunswick. The highway embankment was approximately 12.3m in height when it failed, just short of the design height of 14m. The cause of the slope failure was attributed to the rapid rate of construction and relatively high intensity of loading on the low-strength foundation soils consisting of up to 15m of soft marine clay. The reconstruction effort used 1.4 million scrap tires to make TDA for using it as lightweight fill. TDA was placed within the new embankment, constructed over the site of the failed section. Prefabricated vertical drains (PVDs) were also installed along with a staged construction approach to deal with soft foundation soils. An important element to the reconstruction design was the installation of geotechnical instrumentation, which allowed an observational approach to be undertaken. This approach resulted in modifications to the original design throughout the TDA embankment reconstruction process. This chapter presents the results of the TDA embankment and foundation performance over a 2.3-year period, with emphasis on the behavior of the TDA during construction. Predicted versus field-measured parameters and performance of TDA are presented, including unit weight, temperature, immediate compression, and time-dependent compression. These measured parameters are compared to similar case histories and published values available from the literature. The TDA embankment reconstruction was completed in late fall of 2008, and since then the roadway has performed satisfactorily without any additional maintenance.