Meta-concrete incorporating cubic engineered aggregates (CEAs) is an advanced cement-based composite material with exceptional wave-attenuating capability. However, the soft coatings on CEAs often weaken their interfacial bonding with the mortar matrix, compromising the overall mechanical performance. To address this problem, in this study, the soft coatings of CEAs were pre-treated with sodium hydroxide (NaOH) solutions at varying molar concentrations. Flowability, quasi-static, and dynamic compressive tests were performed to evaluate the influences of chemical modification degree of CEAs and CEA content on the fresh and mechanical properties of meta-concrete. The results showed that increasing the modification degree improved the elastic modulus and static and dynamic compressive strength of meta-concrete but decreased its flowability. Higher CEA content decreased the flowability, elastic modulus, and compressive strength, but enhanced ductility. Both compressive strength and impact toughness of meta-concrete exhibited pronounced strain rate sensitivity, with their trends strongly dependent on the modification degree and content of CEAs. Scanning electron microscopy (SEM) observations revealed a denser interfacial transition zone (ITZ) and reduced interfacial voids after NaOH treatment, confirming that the improved macroscopic performance resulted from strengthened interfacial bonding and enhanced stress transfer at the CEA-mortar interface. A constitutive relation was further established to reproduce the dynamic compressive behaviour of meta-concrete with CEAs across different strain rates. These findings demonstrate that although NaOH treatment improved the mechanical performance of meta-concrete, partial replacement of natural aggregates with CEAs still reduced concrete stiffness and strength, indicating the need for further investigations to improve the mechanical properties of meta-concrete while maintaining its wave attenuation capabilities.
Liu et al. (2026) studied this question.