Shock Absorption of Crumb Rubber and Coconut Fiber

Abstract

Millions of scrap tires are generated annually in the United States and threaten the environmental and public health. Coconut fiber is a biodegradable agricultural waste that is plentiful in many tropical countries. Using these two materials would make the world a better place environmentally. Experiments were done to determine the shock absorption properties of these two materials. A 1-inch thick layer of crumb rubber (shredded scrap tires) with four different grain sizes of 6-14 mesh, 10-30 mesh, 50-80 mesh, and 80-200 mesh reduced impact acceleration from a base value by 15.49%, 20.79%, 31.22% and 38.47%, respectively. Crumb rubber with smaller grain size absorbed shock better than crumb rubber with larger grain size. In a similar study, 1-inch thick coconut fiber reduced impact acceleration from the same base value by 46.44%, 41.89% and 36.13% at 0% (room dry), 100% and 200% water contents, respectively. Coconut fiber is more effective in shock absorption when it contains less water.