Foam stability of 3D printable foamed concrete

This study investigates the susceptibility of precursor foam in 3D printable foamed concrete (3DPFC), particularly in aspects of rheology. The relatively higher yield stress, film liquid withdrawal from unsaturated cement grains and the pumping process raises a concern of considerable foam degradation. Foam stability under the static and dynamic environment is investigated with a wide yield stress range of the base mix (200-1500 Pa) and foamed concrete density range (700-1400 kg/m(3)) is investigated in this study. No major foam instability was found in the static environment with comparison of various wet-to-dry density and porosity models, while the pumping process caused densification for the higher density 3DP-FC. Other than the gravimetric measurements, the X-ray CT scans were performed to analyse the porosity, sphericity and pore distribution changes between the pre-and post-pumped samples. This paper addresses the effect of fluidity on foam stability due to physicochemical interaction on microstructural level, and the producibility of a stable 3DP-FC with a density as low as 700 kg/m(3)