Effect of enhanced coating layer on the bandgap characteristics and response of metaconcrete

Abstract

Metaconcrete is made by partially or fully replacing natural coarse aggregates (NA) in normal concrete (NC) with engineered aggregates (EA). Normal engineered aggregate (NEA) is made by wrapping elastic coating outside spherical heavy core. It was found that mixing NEA in concrete could effectively mitigate stress wave propagation in metaconcrete structure owing to the local resonance of the heavy core of NEA. However, it also reduced the concrete material stiffness and strength because of the low modulus of soft coating that led to relatively large deformation of mortar matrix under loading. To address the issue of low interface stiffness while maintain the local vibration ability of NEA, new enhanced engineered aggregate (EEA) is proposed by placing an additional enhanced coating layer outside the soft coating of NEA. In this study, three types of EEA aggregates composed of three enhanced coating layer materials (i.e., epoxy resin, steel, ultra-high performance concrete UHPC) are considered and their configurations are designed via the software COMSOL. The spall behaviors of enhanced metaconcrete (EMC) mixed with EEA aggregates are examined though numerical simulations. 3D mesoscale models of EMC composed of mortar, randomly distributed natural aggregates and EEA aggregates are built via the software LS-DYNA. The distinction between the bandgap characteristics of NEA and EEA is studied. The effects of enhanced coating layer material on the bandgap of EEA and the performance of EMC with respect to energy absorption capacity, wave attenuation characteristics, and spall strength are studied. The results show that the existence of enhanced coating layer slightly affects the bandgap characteristics of engineered aggregate. Applying an additional stiffer coating layer to make the EEA aggregates can improve the spall strength of metaconcrete mixed with EEA aggregates while its ability in mitigating stress wave propagation and energy absorption is only slightly affected.