Effect of Water Content 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.

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

“…This is consistent with the previous study [1]. However, the trend in Cycle 3 shows an opposite effect.…”

“…This trend is consistent with the previous study [1].  Data from this study is more consistent than data from the previous study [1] since loading direction along grains was used as mentioned earlier.  There is no significant difference among the three wet-dry cycles.…”

“…The slopes of the three cycles are so small that a slight error could change a slope from positive to negative.  Data from this study is more consistent than data from the previous study [1] due to the fixture used with the incline impact tester.  There is no significant difference among the three wet-dry cycles.…”

“…Most products found in retail stores, warehouses, and distribution centers were at some point on a pallet [1]. The Healthcare Packaging Consortium at Christian Brothers University has been conducting wooden pallet research since 2012.…”

“…Fungi, and to a lesser extent bacteria, cause decay in wood as a result of wet conditions [2]. Thus, moisture or water content in wooden pallets has been a focus of several parts of CBU's consortium pallet research [1,3,4].…”