Mechanical behavior and assessment of foamed cement paste under staged cyclic loading

Foamed cement paste has been increasingly adopted recently in engineering practice due to its adjustable density and strength, excellent performance, and convenience for casting in-place. Foamed cement paste is sometimes subjected to cyclic loadings, such as traffic loading and machine vibration. However, limited studies have focused on its dynamic behavior yet. This paper conducted a series of staged cyclic compression tests on the specimen of foamed cement paste with loading frequencies of 1, 2, and 5 Hz. The results showed that an increase in load frequency decreased the peak strength. With the increase of the specimen’s density from 500, 700 to 900 kg/m 3 , the failure modes under cyclic loading gradually transformed from compressive failure, shear failure to splitting failure. An analytical model based on the modified Drucker-Prager Cap model was created to describe the complete backbone curve of foamed cement paste under staged cyclic loading. An empirical equation was proposed to evaluate the reduction of peak strength of foamed cement paste caused by cyclic loading relative to static loading.