Concrete that heals itself and talks to smart cars may be in the future of infrastructure.
Smart infrastructure aims to create roadways and bridges that can communicate with cars and collect their own data.
The Center for Intelligent Infrastructure is working on transmitters that can be laid in with concrete. Luna Lu, professor of civil engineering, said these transmitters are programmed to relay information about the strength and physical condition of the concrete, among other things. The information is relayed between each transmitter and to a main source, which is recorded by the person collecting the data.
Lu said this allows the person handling the traffic to know when to let traffic on the road. It can also determine how much traffic the road can handle and how strong the concrete is once it reaches this critical threshold.
“The (transmitters) that we lay in the concrete are made of a flexible polymer that can bend with the concrete,” Lu said.
Lu said the transmitters can determine when the road loses strength and when and where it needs to be repaired. This data is collected by passing ultrasonic waves through the concrete. These waves reflect back at a given time based on what is present in the structure. The collected data can then be imaged to find the exact location of the problem.
“If you’re using these sound waves, you can generate both 2D and 3D images of the structure on a micro scale,” said Dana Weinstein, professor of electrical and computer engineering and a member of the Intelligent Infrastructure project.
Weinstein said the materials for the transmitters are being made at Purdue. The polymers being used are polyvinylidene difluoride, polydimethylsiloxane and polyimide, all of which are commercially available. But those working on the project are attempting to make their own polymers so they can control certain factors of the polymer and adjust it to their needs.
The transmitters, which are also being made at Purdue, are designed to be cost-efficient and small so they can be produced on a large scale and be made readily available on the market.
“We are trying to make them in such a way that they are able to be printed out by even a normal printer,” Lu said.
The transmitters are strategically placed at regular intervals and are powerful enough to measure a large area. They are also made to be durable so they will not have to be changed very regularly.
Another aspect the team is researching is the ability of the transmitters to communicate with smart vehicles.
“We are trying to develop the transmitters in such a way that they can relay information to smart vehicles,” Lu said. “This is mainly so that the vehicle can be told to slow down or go faster based on factors like the strength of the concrete or the amount of traffic passing over the road.”
Lu said the materials being used in developing the new concrete play an important role in attempting to make it self-healing. The self-healing concrete should be able to fix fissures and cracks in the roadways on its own. This will eliminate the need of shutting down the road or bridge for maintenance or rebuilding.
The team is also considering the transmitters’ durability and their effect on the environment. The materials used to make the polymers and the wires are being modified so they are degradable, Weinstein said.
“We may need to cap the film with an appropriate material to make it waterproof and degradable in the right way,” she said. “We have to be very careful in making sure that we are not polluting the environment because we do not consider the sensors to be disposable. We are making them in large numbers and distributing them in the environment, so its effects on the environment need to be taken into consideration.”
The project has successfully been implemented on three interstates in Indiana, Lu said. California, Kansas and Missouri are among the other states that are planning to adopt this technology.