Did you know that concrete is the most popular building material in the world? It's easy to make, strong, and cheap. But, over time, concrete can get weak, because of water damage. To solve this problem, a scientist from the Netherlands has prototyped something called "bio concrete." Normal concrete is a mix of cement, sand, and stone. But this scientist has added a bacteria (and food for it to eat) to the mixture. This is a special bacteria that wakes up when it touches water. When rainwater goes into a crack in the concrete, it touches the bacteria. The bacteria wake up, eat the food, and produce a material called "limestone." The limestone hardens and fills in the cracks in the concrete. Cracks can be repaired in under two weeks!
This living concrete means that people can save time and money because they aren't making repairs. And the rainwater that used to weaken the concrete is now part of a process that makes it stronger!
What would you design to make a building material stronger? Show us your ideas in the design section.