Mechanical and energy absorption characteristics of foamed concrete under different quasi-static compression tests

• Unconfined, penetration, and rigid lateral compression tests were designed for foamed concrete. • The compression method greatly impacts the failure mode of foamed concrete. • The absorption energy increased several times under rigid lateral constraints. • It is advisable to consider rigid lateral compression as the primary force mode. Foamed concrete often experiences pronounced spalling phenomena during compression, the standard unconfined compressive strength fails to characterize its relevant characteristics accurately. In this study, foamed concrete exhibiting three distinct densities is designed and prepared for the unconfined, penetration, and rigid confined compression tests. It is observed that it exhibits distinct brittle failure characteristics when subjected to unconfined compression. The unconfined penetration compression method displays significant fracture failures independent of density variations, while their load-displacement curves exhibit elastic-plastic stages followed by platform stages before reaching ultimate fracture failure. Compared to low-density foamed concrete, high-density foamed concrete demonstrates enhanced resistance against penetration compression and penetration depth. The splitting failure is mainly attributed to the " cone " extrusion action. Under rigid lateral constraint penetration compression, foamed concrete exhibited an average crushing force efficiency of 132.45 %, significantly surpassing the 50.06 % achieved under unconfined double-platen compression. The total energy absorption performance with identical density under rigid lateral constraint exceeds that under unconfined and double plate compression by over 700 %. It is advisable to consider rigid confining compression as the primary force mode in cushioning energy absorption design since it represents an optimal condition for achieving maximum energy absorption and material utilization.