3D printing of concrete promises practical benefits such as customization of structural shapes, reduction of expensive formwork, and decreased construction time and costs. The 3D print material must be practical to pump, place, and sustain adequate stiffness and surface quality. Vibration of a concrete mixture has been demonstrated to provide a near-instantaneous change in yield stress, allowing for laminar flow during pumping and then, when the material exits the nozzle, an instant recovery of yield strength so that placed material firmly holds its shape and supports subsequent layers of material. This study explores the use of vibration to control essential workability parameters. In the lab, a modified rheometer is used to characterize the rheology of paste, mortar, and concrete both under vibration and at rest. Accelerometers are used to measure the vibrations as they propagate through concrete. Numerical simulation, validated by experimental results, helps to understand the effect of vibration, and predict the behavior of concrete flow during full scale construction.