Fast penetration testing of printable concretes with a portable device: robustness and calibration

Concrete 3D printing demands rheological control tools tailored to this emerging construction technology. Conventional rheometry is often unsuitable for routine monitoring in industrial environments. This study investigates the use of a fast penetration test with a portable device as a simple, effective method to evaluate yield stress and structuration rate of printable concretes. Emphasis is placed on robustness, assessed through measurement variability rather than absolute values. Tests on clay-based reference pastes identify probe geometries minimizing operator influence and data dispersion. Probe and sample size effects are also examined. Calibration on reference pastes establishes geometry-specific conversion factors between penetration force and yield stress. These factors are then used to monitor yield stress evolution in printed concrete, with results compared to those from a pocket vane test. Findings indicate that the fast penetration method yields more robust, consistent measurements, supporting its suitability for rheological quality control in concrete 3D printing.