Smart Concrete Can Generate Electricity

Researchers have come up with an advanced design of the most widely used construction material—concrete—for its use in next-generation smart infrastructure, building, and other civil engineering projects.

A team from the University of Pittsburgh has developed a metamaterial concrete that can include compression, sensing, and energy-harvesting capabilities. The material paves the way for customized material that engineers and builders can design for its specific purpose in a civil-engineering project, the researchers said.

The demand for more sustainable and ecologically friendly advanced materials for the construction industry was a key impetus for the development of the material, which was the work of researchers—including Amir Alavi, assistant professor of civil and environmental engineering—in Pitt's Swanson School of Engineering.

“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," he said.

Researchers achieved this by introducing what he called "a metamaterial paradigm" into the development of the material, which imbued it with an upgrade in its properties, Alavi said. “This project presents the first composite metamaterial concrete with super compressibility and energy-harvesting capability,” he said in a press statement.

Concrete With Advanced Features

The researchers—who collaborated with scientists from Johns Hopkins University, New Mexico State University, the Georgia Institute of Technology, and Beijing Institute of Nanoenergy and Nanosystems—built on previous research to develop self-aware metamaterials and their potential use in applications like smart implants.

They applied the notion of metamaterial design introduced in that work to concrete to make it possible for the common material to be specifically designed for its purpose, researchers said.

This capability means that during the creation of the material itself, various characteristics of the material—such as brittleness, flexibility, and shapeability—can be fine-tuned for the purpose for which it will be used, the researchers said. This ultimately will allow builders to use less of the material, saving on resources and waste without sacrificing strength or longevity, they said.

The material itself is composed of reinforced auxetic polymer lattices embedded in a conductive cement matrix that's enhanced with graphite powder, serving as an electrode and allowing the material to general energy, the researchers said. This aspect of the material works because the composite structure induces contact-electrification between the layers when triggered mechanically, they said.

While the material cannot produce enough electricity to send power to the electrical grid, the generated signal will be more than enough to power electronics such as roadside sensors. Moreover, when activated by mechanical stimulation, the electrical signals self-generated by the metamaterial concrete also can be used to monitor damage inside a structure built with it, or to monitor earthquakes while reducing their impact on buildings, the researchers said.

The Future of Smart Construction

Researchers published a paper on their work in the journal Advanced Materials. They reported that in testing, the material demonstrated that it can compress up to 15% under cyclic loading and produce 330 μW of power.

Eventually, structures built with the material can even provide power to chips embedded inside roads to provide navigational assistance for self-driving cars in case GPS signals are weak or LIDAR is not functioning as it should, the researchers said.

The material's ability to be customized for applications and its compression capabilities also make it extremely useful for a host of next-generation civil engineering projects, Alavi said. "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," he said.

To help make some of these future applications a reality, the team from Pitt is partnering with the Pennsylvania Department of Transportation (PennDOT) through the university's IRISE Consortium to develop the concrete for use in road construction in Pennsylvania, the researchers said.