What is the next ultra-strong building material the world is going to use in its structures? You've been using it since you were a child, it's been under your nose the entire time. Sand. The stuff sand castles are made out of. However, whenever you've made a sand castle it's usually ended a crumbling mess even if you built it well. This is where geotechnical engineering comes in. The aim is to make regular sand/dirt a stronger material so that we could eventually sturdy structures on the inexpensive ground we stand on. We already use some of the technology in highway projects in our world today. But there could be a fruitful future in mechanically stabilized earth. 

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Credit: Practical Engineering

A YouTube channel called Practical Engineering has shown how this is possible. They foresee a future where instead of the molecular bonds that steel and concrete require (which produces fossil fuels in its creation), sand is could be an all natural alternative. But how do we strengthen something so 'fluid' as the sand that immediately falls away when we scoop a handful of it up from the beach? Practical Engineering points out that when a force is applied to soil, the sliding planes are infinite and therefore something cannot stand on it without making the soil's rigidness fail. 

Reinforcing elements are the answer. Sand requires more reinforcing elements because it cannot stand up vertically with causing a slope. Concrete can stand at a vertical face due to the mechanical stabilizing that the engineers have secured within it or around it. So the YouTube channel explains that flat pieces of fabric are layered between the soil which creates a reinforcement and strengthens the sand. This in a real life example would obviously translate to a sturdier soil reinforcement method with sturdier materials. They show that MSE (mechanically stabilized earth) walls are used in highway projects and then covered up with patterned walls that are quite nice to look at but are always an example of soil that has been stabilized with reinforcements and are actually super-sturdy pieces of engineering. EIT Stock Image

Steel reinforcements - that can be layered in between soil - are utilized in the civil engineering world today, but the future of a cost-effective fabric that could be layered between soil could be the future of reinforced soil. The current issue with using steel reinforcement is that corrosion can occur, however, the patterned panels can preserve some of the corrosion that would occur due to wind and water, however, most engineers point out that the panels are basically just for decoration. However, some galvanized steel reinforcement blankets can last up to seventy-five years according to industry insiders, and that can be layered in between soil to mechanically reinforce it. 

Do give the video a watch, they balance a car on a cube of reinforced soil to show how sturdy it can actually be.