Concrete is the most commonly used building material and dates back to the Roman Empire. However, engineers from the University of Pittsburgh are attempting to redesign it for the 21st century.
Concept artwork depicting a new metamaterial concrete in use on a highway. Image Credit: Amir Alavi via Midjourney
New research introduces metamaterial concrete for the development of smart civil infrastructure systems. The engineers introduce a novel concept for lightweight, mechanically-tunable concrete systems with incorporated energy harvesting and sensing capabilities.
The paper, "Multifunctional Nanogenerator-Integrated Metamaterial Concrete Systems for Smart Civil Infrastructure," presents a new concept for lightweight and mechanically-tunable concrete systems that have integrated energy harvesting and sensing functionality.
Modern society has been using concrete in construction for hundreds of years, following its original creation by the ancient Romans. Massive use of concrete in our infrastructure projects implies the need for developing a new generation of concrete materials that are more economical and environmentally sustainable, yet offer advanced functionalities. We believe that we can achieve all of these goals by introducing a metamaterial paradigm into the development of construction materials.
Amir Alavi, Study Corresponding Author and Assistant Professor, Civil and Environmental Engineering, University of Pittsburgh
Alavi and his colleagues have previously made self-aware metamaterials and investigated their use in applications such as smart implants. The use of metamaterials in the making of concrete is introduced in this research allowing the material to be specifically designed for its purpose.
Brittleness, flexibility, and shapeability can all be fine-tuned during the material’s development, allowing builders to use less of the material without compromising on strength or longevity.
This project presents the first composite metamaterial concrete with super compressibility and energy harvesting capability. Such lightweight and mechanically tunable concrete systems can open a door to the use of concrete in various applications such as shock absorbing engineered materials at airports to help slow runaway planes or seismic base isolation systems.
Amir Alavi, Study Corresponding Author and Assistant Professor, Civil and Environmental Engineering, University of Pittsburgh
Not just that, but the material can generate electricity. While it cannot produce enough electricity to power the grid, the generated signal is more than enough to power the roadside sensors. Under mechanical excitations, the electrical signals generated by the metamaterial concrete could also be used to track damage within the concrete structure or to evaluate earthquakes while lowering their effect on buildings.
These smart structures could finally power chips integrated inside roads to assist self-driving cars in navigating on highways when GPS signals are too weak or LIDAR is not functioning.
The material is made up of reinforced auxetic polymer lattices embedded in a matrix of conductive cement. When mechanically triggered, the composite structure stimulates contact-electrification between the layers.
The conductive cement, which has been improved with graphite powder, continues to serve as the system's electrode. Experiments revealed that the material could indeed compress up to 15% under cyclic loading while producing 330 μW of power.
Through the IRISE Consortium at Pitt, the investigators are collaborating with the Pennsylvania Department of Transportation (PennDOT) to advance this metamaterial concrete for use on Pennsylvania roads.
The study included researchers from New Mexico State University, Johns Hopkins University, the Georgia Institute of Technology, the Beijing Institute of Nanoenergy and Nanosystems, and Pitt’s Swanson School of Engineering.
Journal Reference:
Barri, K., et al. (2023). Multifunctional Nanogenerator‐Integrated Metamaterial Concrete Systems for Smart Civil Infrastructure. Advanced Materials. doi.org/10.1002/adma.202211027.