Permeability of Uniform and Mixed-Size Tire Chips under Different Loading Conditions

Abstract

The permeability of uniform and mixed-size (volume based) tire chips under various overburden pressures is determined. Tire chips sizes of 5.08, 10.16, and 15.24 cm are used. The permeability tests are conducted using sample layers of 15.24-, 30.48-, and 45.72-cm thickness. The vertical and lateral permeability data of uniformly sized chips under no overburden are in the range of coarse gravel. The mixed-size tire chips have permeability in the range of coarse to very coarse gravel under no overburden. Under overburden, the compressibility of the uniformly sized tire chips increases with tire-chip size and decreases with layer thickness. There is a general trend of decrease in permeability with increase in overburden pressure. In the case of uniformly sized chips under overburden, the 5.08-cm chips have the highest permeability and the 15.24-cm chips have the lowest permeability. The mixed-size tire chips have higher permeability than the uniformly sized tire chips. In general, the permeability of uniform and mixed-size tire chips is in the range of coarse gravel.