Evaluating Early-Age Interlayer Bond Development in 3D Printable Concrete Using Ultrasonic Testing скачать в хорошем качестве

Evaluating Early-Age Interlayer Bond Development in 3D Printable Concrete Using Ultrasonic Testing

Presented By: Zahra Miri, University of Waterloo Description: 3D Concrete Printing (3DCP) offers a groundbreaking method for construction, depositing concrete layer-by-layer via a nozzle mounted on a gantry or robotic arm. By removing the need for formwork, 3DCP enhances cost efficiency, accelerates project timelines, and promotes sustainability in construction practices. However, 3DCP faces technical challenges, particularly the formation of weak interlayer bonds between deposited layers, which can lead to anisotropy and impact structural integrity. This research focuses on applying ultrasonic testing (UT) to detect weak interlayer bonds at early ages in 3D-printed concrete. Ultrasonic pulse measurements were performed concurrently with splitting tensile tests to monitor bond development at ages 1, 3, and 7 days. Specimens (100 mm cubes) were prepared using commercially available printable concrete, cast in two layers with a 1-hour time gap between them—matching the final setting time of the material. Two interlayer conditions, dry (exposed to air) and wet (misted with water before the second layer), were examined to study the impact of moisture conditions on bond strength; these samples were then compared to a control scenario without any interlayer. By employing ultrasonic measurements, this study seeks to identify weak interlayer bonds early, providing critical insights into the role of interlayer moisture conditions in bond formation. The results will help refine bonding strategies in 3DCP, improving structural performance and consistency in 3D-printed concrete applications. This work highlights ultrasonic frequency analysis as a key non-destructive testing technique for assessing interlayer bond quality in early-age concrete, supporting industry-wide efforts to enhance the reliability and durability of 3D-printed structures.