Improving the compressive performance of foam concrete with ceramsite: Experimental and meso-scale numerical investigation

Highlights: • The strength match between foam concrete and ceramsite aggregates determines the failure modes. • The meso-scale model reasonably reflects the macroscopic mechanical behavior of the specimens. • The performance is improved by optimized design of the components parameters based on the strength match mechanism. As a new composite material by adding ceramsite into foam concrete, lightweight aggregate foam concrete (LWAFC), mainly composed of cement, water, performed foam, and ceramsite, exhibits excellent compressive performance. To facilitate its application in structure protection where energy absorption is concerned, the responses of ceramsite foam concrete were investigated experimentally and numerically with meso-scale model. First, a compression test (loading rate of 5 mm/min) on cubic LWAFC specimens with side length of 100 mm was conducted, in which two different failure modes, namely foam concrete failure and through-ceramsite failure, were observed. Meanwhile, it was found that the compressive strength of LWAFC specimens increased with increasing foam concrete density. Based on synchrotron radiation CT on foam concrete, a two-dimensional meso-scale numerical model with size of 100 × 100 mm was established. The failure mode, compressive strength, plateau stress, and energy absorption capacity of the LWAFC with an averaged loading rate of 1 m/s were systematically investigated. In particular, the underlying mechanism for the two distinctive failure modes was revealed as the strength match between the foam concrete and ceramsite. Subsequently, the performance of LWAFC was significantly improved by reasonably designing the foam concrete and ceramsite with optimized strength match.