Multifunctional Nanogenerator-Integrated Metamaterial Concrete Systems for Smart Civil Infrastructure.

Multifunctional construction materials can form the building blocks for next generation smart civil infrastructure systems. Such integrated infrastructure systems can self-sustain their operations, offer designated structural behavior, and achieve a range of functionalities. Concrete is known as the most paramount construction material worldwide. Creating multifunctional concrete materials with advanced functionalities and mechanical tunability is a critical step toward reimagining the traditional civil infrastructure systems. Here, we present a new class of lightweight composite metamaterial concrete with unprecedented mechanical properties along with energy harvesting and sensing functionalities. The proposed nanogenerator-integrated metamaterial concrete system is created via integrating the mechanical metamaterial and triboelectric energy harvesting paradigms. The metamaterial concrete system is composed of reinforcement auxetic polymer lattices with snap-through buckling behavior fully embedded inside a conductive cement matrix. We rationally design this composite structure to induce contact-electrification between its layers under mechanical excitations/triggering. The conductive cement enhanced with graphite powder serves as the electrode in the proposed system, while providing the desired mechanical performance. Proof-of-concept prototypes are built with different geometries and reinforcement levels. Experimental studies are conducted to investigate the mechanical and electrical properties of the designed prototypes. The proposed metamaterial concrete systems are tuned to achieve up to 15% compressibility under cycling loading. The power output of the nanogenerator-integrated metamaterial concrete prototypes reaches 330 μW. Furthermore, we demonstrate the self-powered sensing functionality of the nanogenerator concrete systems for distributed health monitoring of large-scale concrete structures. The metamaterial concrete paradigm can possibly enable designing concrete systems with a broad range of properties such as low/high stiffness, scalability, and shapeability for prefabricated elements. Finally, we highlight the potential of the proposed metamaterial concrete paradigm to transform the current design practice in concrete industry. This article is protected by copyright. All rights reserved.