Conclusions

Based on this experimental and theoretical study, the following conclusions can be advanced:

1. Three-dimensional triaxial P- and S-wave velocity testing can be used to determine the five elastic constants necessary for modeling the behavior of anisotropic tire shred material.

2. The test results demonstrated the cross-anisotropic nature of the tire shred material. It was also observed that anisotropy increased with stress (stress-induced anisotropy).

3. The data obtained from three-dimensional triaxial P- and S- wave propagation tests can be used to calculate an elastic-perfectly plastic material model for the tire shreds material. The model also represented the variation of $G/G_{max}$, that is usually found in traditional analysis of dynamics of frictional media.

4. Further testing is necessary to mitigate the excessive deformation caused by unload-reload cycles in the current program. Additional testing would also target redundant measurements of six elastic constants so as to evaluate the negative Poisson's ratio determinations from the current program.