Effect of Wet-Dry Cycles on Compressive Strength and Impact Properties of New Softwood Pallets

Abstract

The effect of water content on compressive strength and impact properties of new softwood pallets was determined through four experiments. A static compression test was performed on pallet specimens with various water contents. The compressive strength drop rate was 3.4 pounds per square inch (23442 Pascal) per 1% increase of water content. A drop test was performed on pallet specimens with various water contents and cushioning materials at 12-inch (0.3048-meter) drop height. Impact acceleration increased at the rate of 0.14g per 1% increase in water content. A drop test was also performed on pallet specimens with various water contents at 18-inch (0.4572-meter) drop height. Energy absorption reduced at the rate of 0.16% per 1% increase of water content. Thus, softwood pallets, which are often left outdoors and subjected to rain water, have two potential problems with the increase in water content, i.e., reduction in compressive strength under static loading and increase in impact acceleration felt by boxes on these pallets.