Effect of Temperature and Humidity on Crush Strength of Cellulose Fiberboard Assemblies

Cane fiberboard is widely used as the impact absorption and thermal insulation material in overpacks for radioactive materials shipping packages. The study described here investigated the properties of cane fiberboard assemblies under environmental conditions important to radioactive materials packaging applications. Tests were performed for loading perpendicular and parallel to the planes of the fiberboard sheets for both slow and impact strain rates, at high and low temperature and at high and low humidity. Under high temperature and high humidity conditions, the stress/strain response of the assemblies was close to the response at ambient conditions. However, for low temperature and impact strain rate conditions for specimens loaded parallel to the planes of the fiberboard sheets, an initial stress spike was found. The cause of this transient, high, initial stress was determined to be the stiffening effect of the glue layers used to bond the fiberboard sheets together.