Rheology-based determination of injectable grout fluidity for preplaced aggregate concrete using ultrasonic tomography

With the increasing use of preplaced aggregate concrete in construction, the grout filling in preplaced aggregate concrete is important for ensuring proper consolidation and high mechanical performance. This paper proposes a framework for determining the injectable grout fluidity for preplaced aggregate concrete according to the rheological properties of the grout mixture, which are associated with the filling performance for the given aggregates. To assess the grout filling, cost-effective, nondestructive ultrasonic pulse velocity (UPV) testing was performed, and ultrasonic tomography images were constructed for visually identifying internal air voids, which were verified by high-resolution micro-computed tomography. Rheometer tests evaluated the rheological properties of the grout mixtures. The UPV-based void-detection results and grout rheological properties were employed to determine the injectable grout fluidity range.