Date of Award


Degree Type


Degree Name



Civil and Environmental Engineering

First Advisor

Gnyp, A.


Engineering, Automotive.




A comprehensive investigation of the cryogenic recovery of tire rubber was conducted with laboratory, pilot plant and industrial equipment. Experiments were conducted with specimens of tire rubber to determine cooling curves for: (1) Scrap tire rubber dipped in liquid nitrogen. (2) Scrap tire rubber cooled by nitrogen vapour. (3) Virgin tire rubber dipped in liquid nitrogen. (4) Different size cubes of tire rubber cooled simultaneously by nitrogen vapour. (5) Tire rubber cooled and then recooled to investigate material degradation. Electron microphotographs of scrap and virgin tire treads were compared in terms of physical characteristics. The used tire rubber specimen appeared to have a granular structure. Air trapped in the interstices hindered the heat transfer process. On the other hand, the virgin tire specimen appeared to be homogeneous. This structure enabled the virgin material to cool at a higher rate. Electron photomicrographs of ambiently and cryogenically ground rubber crumbs were also compared. The ambiently ground rubber displayed more surface area than the cryogenically ground material. This increase was created by the torn edges of the ambiently ground rubber. The faceted surfaces of the cryogenically processed rubber provide smoother surfaces of lower area. Experimental and theoretical data were used to design a small fine-grind system which was proposed for the processing of ${3\over 8}$ inch pellets of tire rubber to a fine size less than 30 mesh. When frozen tire chips are passed through a hammermill, an entanglement of steel and nylon fibre results. Separation of this entanglement by various means was thoroughly investigated. Theoretical and experimental data were applied to the modifications of the industrial-size plant in Cambridge, Ontario. The improvements to the industrial system made it more efficient. A number of recommendations have been made for continuation of this basic investigation. (Abstract shortened by UMI.)Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1993 .M271. Source: Masters Abstracts International, Volume: 33-04, page: 1278. Adviser: Alex W. Gnyp. Thesis (M.Sc.A.)--University of Windsor (Canada), 1993.