Porosity, gradient and impact velocity effects on compressive response of foamed concrete

Foamed concrete is widely used in various engineering fields. This paper reports the effects of porosity, gradient and impact velocity on the mechanical behavior and deformation mechanism of foamed concrete. Mesoscopic models are built up based on the Voronoi diagram and space holder technique. The finite element analysis of which material parameters has been verified by previous experimental results, is conducted on mesoscopic models. Results reveal that the compressive strength of foamed concrete shows an upward trend with the porosity decreasing, which can be well described by an exponential law. It has been indicated that foamed concretes with a similar porosity but different pore sizes and pore distances possess nearly consistent stress–strain curves as the regularity and pore shape are both fixed. This is because of their similar deformation mechanism, namely array deformation distribution. Furthermore, compared with uniform specimen, graded foamed concrete generates initial deformation in the region with the highest porosity under an impact velocity of 1 m/s, in which the inertia effect is inapparent. Besides, the effect of impact velocity is investigated. Because of the inertia effect, the peak stress of the impact end of uniform foam is obviously higher than that of the support end. However, graded foams can adjust the loading process compared with uniform ones and thus the peak stresses of two ends can be controlled by the gradient configuration.