Changes in the dynamic modulus of elasticity and bending properties of railroad ties after 20 years of service in Taiwan

An ultrasonic-wave technique and transverse vibration nondestructive evaluation methods were used to evaluate the dynamic modulus of elasticity and bending properties of wood from railroad ties of creosote treated from 7 species of wood removed from service after 20 years. Two NDE techniques and static bending tests were conducted on railroad ties, and lumber and specimens subsequently cut from the ties. Regression analyses gave a reasonably useful correlation between the ultrasonic-wave-based dynamic modulus of elasticity of the ties and lumber and the corresponding flexural properties of lumber and small clear specimens determined by 2 NDE techniques and static bending techniques, respectively. The results showed that wood from the creosote-treated railroad ties removed after years of service had sufficient potential residual strength for use in exterior structural applications.