Non-destructive testing to characterize interlayer bonds of idealized concrete additive manufacturing products

Abstract We examine non-destructive testing (NDT) techniques that characterize the interlayer bond quality of idealized 3-D printed concrete, simulating a layup bond, in-situ. An experimental study evaluates four NDT methods (x-ray radiography, ultrasonic pulse velocity (UPV), vibration resonance, and multi-element array ultrasonics) to idealized, layered concrete specimens that simulate layers of a 3-D printed structure. The interlayer bond strengths of the specimens were measured directly using split-prism load testing. X-ray radiography and multi-element array ultrasonic test data demonstrate best correlation with measured interlayer bond strengths. We used multi-element array ultrasonic test data to classify bond interface quality into well bonded, weakly bonded, and debonded cases.