A Sidewalk That Sips Water? One Middle Schooler Makes a New Concrete Mix to Stop Flooding
For the seventh year, The Lemelson Foundation is awarding $100 prizes to outstanding young inventors in Society Affiliate Fairs with middle school participants across the country. The prize was created to recognize young inventors whose projects exemplify inventive thinking by identifying challenges in their communities and creating solutions that make a difference.
For most of us, a big rainstorm means grabbing an umbrella or staying inside, but for Luca Durham, a 6th grader from Miami, Florida, a major downpour sparked an idea for a science project. After watching his neighbor’s driveway flood and spill water onto the street, making it difficult to drive, Luca began to question whether there was a better way to manage rainwater.
“Maybe there was a way to make concrete that could soak up water instead of flooding the street,” he wondered.
Luca dove into research on a material called porous concrete, designed to allow water to pass through it. However, he quickly discovered the concrete’s flaws; existing versions often aren’t strong enough for real-world use and can get clogged with dirt. He wanted to find a stronger and more reliable alternative.
“One day, after taking a shower, I stepped on my stone bathmat and noticed how fast it absorbed the water from my feet,” Luca shares. “It was kind of like a sponge, and I wanted to know what it was made from. I found out it was made from diatomaceous earth, which comes from tiny, fossilized algae.”
This discovery led to a new question: could Luca add diatomaceous earth to concrete to create a stronger, more absorbent material?
“I wanted to find additives that could help concrete drain water but still be strong. I also looked for materials that were sustainable or things people usually throw away, because I wanted my project to help both people and the environment,” he says.
First, Luca chose crushed oyster shells and seashells, which are typically discarded as waste. Their curved shapes create tiny gaps in the concrete, helping water flow through. Next, he added charcoal, a porous material that can be made from waste wood and is known for its filtering properties. He also included gravel, because it’s already known to make porous concrete stronger and give water clear paths to drain. Lastly, he added diatomaceous earth, the material used in his bathmat, which he hoped would increase the concrete’s ability to absorb water.
Luca tested them for drainage, absorption and strength. His hypothesis was that a mix of 30% diatomaceous earth and 70% cement with shells would work best because the shells could create spaces for water to flow and the diatomaceous earth could soak up extra water. In the end, Luca found that the best mix was 30% diatomaceous earth and 70% cement with gravel. “This project shows that using sustainable materials in concrete can help reduce flooding, improve water drainage and create a more environmentally friendly infrastructure,” Luca explains.
The tests didn’t always go smoothly, Luca shared. At first, he used the wrong ratio of cement to additives, and it was difficult to get all of his seashells and charcoal pieces to be the same size. While he acknowledged that he got frustrated at times, Luca said the experience taught him not to give up.
“I loved seeing the science in action and figuring out which materials made the biggest difference,” Luca says. “But the best part was realizing that I might have created something no one has ever tried before. It felt amazing to see my idea actually work and to think I might have invented a new kind of concrete that could help people.”
Luca entered his project in the South Florida Science and Engineering Fair, where he won the Lemelson Early Inventor Prize, a win that Luca says, “inspires me to keep thinking of new ideas and ways to solve problems.” Next, he plans to strengthen his concrete by adding carbon fiber strips so that it can hold more weight. “My dream is to create a sidewalk material that is strong, eco-friendly, and helps keep streets from flooding.”
