LARGE-SCALE TRIAXIAL TESTING OF SUSTAINABLE TDA BACKFILLING ALTERNATIVES

Abstract

One billion scrap tires are generated worldwide every year. Advanced countries have a higher rate per capita of generating scrap tires. In 2015, Canadians disposed of 37 million tires; while, nearly 250 million scrap tires were generated in the United States. The number of disposed of tires every year in Nova Scotia is equal to the number of residents. Due to environmental considerations, landfilling scrap tires is no longer allowed in Nova Scotia and stockpiling tires is not a viable option either as it is a fire hazard and a breeding ground for mosquitos and vermin. One of the most environmentally friendly methods to recycle scrap tires is to shred scrap tires into a product called Tire Derived Aggregate (TDA). While the TDA use has been on the rise recently, research on the mechanical properties of TDA is very limited. In this research, a series of triaxial tests were conducted to evaluate the mechanical properties of TDA and TDA/soil mixtures with varying compositions of TDA and fine and coarse aggregates (i.e. TDA/sand mixtures and TDA/gravel mixtures). Each sample set was subjected to at least three different confining pressures. The results of the tests were presented and compared to the results of other researchers. Based on the tests results, empirical equations representing a number of key geotechnical properties were proposed.