A team at Rowan University in New Jersey, led by Islam Mantawy (civil engineering) and Behrad Koohbor (mechanical engineering), has developed a method to measure how 3D printed concrete moves and shrinks during printing and curing. The work was published in the journal Experimental Mechanics.
The method builds on digital image correlation, which compares camera images against a reference shot to measure deformation. A printed piece has no such reference until it is finished, so the team runs the analysis in reverse: it starts from images of the completed structure and works back through thousands of frames taken during printing, using the concrete's own surface roughness as the tracking pattern. This shows how the lower layers react to the weight of each new layer, even in the first moments after it is laid down.
Why it matters to us: when you print without moulds, the lower layers carry everything above them while they are still fresh. Being able to see that early deformation is key to tall, thin walls, and to knowing a section will hold its shape before the last layer goes on. It is also a step toward printers that can check their own work.