Precast concrete sandwich panels with recycled tire crumb rubber and expanded polystyrene foam cores under low-velocity drop weight impact

Structural behavior of precast concrete sandwich panels under low-velocity drop weight impact is presented in this paper. Three types of concrete panels are considered namely, solid concrete panel (SCP), concrete sandwich panels containing recycled tire crumb rubber as core (CRSP), and expanded polystyrene foam as core (FSP). The panels are reinforced with steel mesh or steel fibers. A total of 12 panels are cast in this study. Six panels are reinforced using steel mesh, and the other six panels are reinforced using steel fibers. The impact test is carried out by dropping a weight from a varying height to input impact energy, which can cause various levels of damage for all specimens. The structural performance is discussed in detail, including failure modes, impact force, deflection, and strain. It is found that the core material greatly affects the structural response of the precast concrete panels. The sandwich panel containing recycled tire crumb rubber performed well in terms of rebounding force, permanent deflections, and damage behavior by partially absorbing the impact energy in both types of reinforced concrete panels. In CRSP and FSP, the maximum deflection to permanent deflection ratio rose from 1.19 in SCP to 2.67 and 2.01, respectively. A decrease of 70% in strain value from the first impact to permanent strain was recorded in CRSP when reinforced using conventional steel mesh. In comparison to its counterpart FSP, the CRSP exhibited a significantly smaller fracture width on the tension face as a result of the core's ability to dissipate impact energy, resulting in lower deflections and less damage to the panel. The CRSP reinforced with steel fibers demonstrated comparable performance to the counterpart FSP in terms of energy absorption and deflection reduction; however, it performed noticeably better than the SCP reinforced with steel fibers by reducing residual deflection by 51.8 mm. Consequently, recycled tire crumb rubber can be used as a sustainable alternative to traditional core materials in precast concrete panels.