Assessing adhesion and glue-line defects in cold-pressing lamination of glubam

Abstract Nondestructive ultrasonic testing is known as a very efficient inspection method for detecting defects in concrete and steel structures. In order to apply this method for inspecting the quality of the cold-pressing glue-lines in glued laminated bamboo (glubam) components, a series of rheological performance tests and the ultrasonic transmission tests were conducted on modified adhesives and on glubam specimens with cold-pressing glue-lines, respectively. Focuses are on the gap filling ability of the adhesive and the defect threshold of the glue-line by using nondestructive ultrasonic testing. An optimal modified adhesive and the corresponding control spray amount were provided for manufacturing glubam components based on the rotational viscosity test and proposed sagging test. The initial amplitude of received signal is selected as the acoustic parameter to identify the glue-line defects in glubam specimens, and a defect criterion is proposed by using the ultrasonic transmission method. Verification test results indicate that the proposed defect judgment method has good feasibility and accuracy.