Concrete may have found it's killer app in graphene foam, a new form of structural material that's lighter than cork but stronger and more stable than plastic, researchers say. Graphene foam could be used as lightweight building material for everything from bullet-resistant glass to lightweight protective armor for the military. The foam could also help protect against earthquake damage because it is so strong and resilient to stress. Researchers made the new material by synthesizing a lightweight foam of graphene sheets by suspending them in a polymer solution. It's made up of graphene sheets, which are a pure form of carbon that's just one atom thick. The tiny flakes are held together by bonds, but these bonds are not as strong as covalent chemical bonds that are found in most materials and metals. "Graphene foam is able to recover its mechanical strength, even when being subject to the highest level of strain," said researcher Liangbing Hu from the Shanghai University of Engineering Science in China. Graphene foam made of graphene sheets. (Image credit: American Chemical Society) Hu and his team were able to produce graphene foam that was 5 times stronger than steel. The foam was extremely lightweight — just 1 gram per cubic centimeter. It was also very strong at temperatures up to 1,732 degrees Fahrenheit (900 degrees Celsius) and the foam can be made in a variety of shapes. [9 Ways You Can Inspire Children's Minds] The new foam was developed at the same time as another form of foam made up of ultra-thin graphene flakes, which is more stretchable than the graphene foam developed by Hu's team. The lightweight nature of the material makes it practical for use in areas where weight reduction is a big issue. For instance, the material could be used for making self-healing windows and bullet-proof glass that can also repel water. "This new class of lightweight foams has the potential to greatly improve properties of materials while saving tremendous amounts of weight," Hu said. "We expect graphene foams will be widely used in a wide range of applications ranging from bullet-proof glass to structural materials for buildings and to lightweight armor for soldiers." Graphene is already making a big impact in many fields. The material is super-strong, yet very light and flexible. It has also been used to create a strong but lightweight adhesive and to produce materials that can convert solar energy into electricity. The new foam was described in a study published March 17 in the journal Nature Communications. Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.