Studies of Influence of Moisture Content in Cellulose Fiber Cement Boards on Wave Parameters Using Non-Contact Ultrasound

摘要

The paper presents results of studies focused on evaluation of influence of moisture content of cellulose fiber cement boards using non-contact (air-coupled) ultrasonic technique. Cellulose fiber cement boards are relatively new ecological materials commonly used in architectural engineering for many external and internal applications such as buildings elevation or as walls and roofs covering materials. The theoretical studies of wave propagation in plates served to identification of the wave mode measured in the boards. Ultrasonic examinations were performed using Lamb waves. Independently, for the same boards the moisture content was evaluated by nondestructive testing using dielectric humidity measuring device. The obtained results confirmed applicability of the non-contact ultrasonic technique using Lamb waves to studies of cellulose fiber cement boards. It was observed high sensitivity of the method to the moisture content. Based on the obtained results one can conclude that following appropriate calibration, the method can be potentially applied as a tool for evaluation of moisture content in cellulose fiber cement boards.