Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete

Abstract

This research explores the structural properties of fresh concrete. The work is relevant wherever green, or uncured, concrete must be load-bearing. In traditional concreting, rigid forms mold and protect young concrete, and these forms are not removed until the maturing material has developed considerable load-bearing strength. Conversely, an automated construction technology under development at the University of Southern California, proposes to rapidly fabricate civil structures additively — layering continuous ribbons of fresh unconfined concrete — the freshly layered concrete must be load-bearing immediately upon placement. This is an unprecedented structural requirement, and little has been done to substantiate uncured concrete in such a load-bearing capacity. With emphasis on expedient experimental techniques, early maturity, and time-dependent constitutive modeling, this research develops the engineering necessary to erect these structures safely.