It’s safe to say that if you’re reading this article on this particular Web site, you probably already think the Earth is pretty amazing. Now there is one more reason why earth—that is to say, dirt itself—deserves our respect and admiration. Practical Engineering put together a few examples of how plain, ordinary dirt can become an incredibly sturdy building material. All it needs is a little reinforcement, but that doesn’t have to come in the form of steel beams or carbon fiber. Paper, fabric, or even a window screen can lend a hand to create a dirt ‘brick’ capable of holding up a human being or even a car.
In the video above, Grady Hillhouse demonstrates the impressive power of Mechanically Stabilized Earth (aka MSE or Reinforced Soil). Hillhouse, a professional civil engineer, and a guy who likes to get his hands dirty, discusses the pitfalls of soil-only attempts at construction using loose, dry sand as an example. The video gets fairly technical, but it’s easy to understand the principles if you’ve ever packed wet beach sand into a cup or mold and tipped it out to build a sand castle. The wet sand, or other type of soil, holds it shape, but it isn’t capable of bearing much weight.
That’s where the reinforcements come into play. By packing sand or dirt in layers between sheets of paper, the resulting ‘confining pressure’ helps balance and distribute the weight to create an ultra-strong building material. The mind-blowing thing is that we’re not talking about a specially made or spectacularly thick piece of paper. Hillhouse uses paper towels to demonstrate the principle in a sand tower, topping it with a 15-pound block to show off its remarkable strength.
Hillhouse points out that MSE is already being used in cities around the world, although most people don’t realize it. Because of the low cost and easy availability of dirt, MSE is a promising construction technique where budget constraints and sustainability are key.
Images via Practical Engineering (screenshots)