Driveways... Let's Keep Them Clean

eCYBERMISSION is a national competition for students in 6th, 7th, 8th, and 9th grade based on science, mathematics, engineering, and technology. Groups of students across the country compete by performing experiments that will ultimately benefit the community. Early registration for this competition began on July 9th, 2012 and the first registration deadline was on October 15th, 2012. After registering, the teams begin their experiments and begin to build their Mission Folders online. This will consist of their entire lab report in a single folder. This mission folder is due for judging on March 1st, 2013.

 

My group consisted of Teresa Price, Elizabeth Dowds, Ryan Brandt, and myself. We decided early in the competition to test the best driveway material that would not crack or collapse. Our biggest concern was the absorption of water through the material. We wanted to prevent driveways from collapsing, eroding, and cracking from inclement weather. Another concern to consider is the water left on the driveways which will runoff into nearby aquatic ecosystems. Often driveways are exposed to gasoline, fertilizer, pesticide, and insecticide. With the precipitation build up on the driveway, it can wash away the pollutants into places like roadside drains or even a nearby lake or stream. From there the chemicals can end up in oceans and negatively affect the local aquatic ecosystems. However, if the pollutants were absorbed through the driveway itself, they would gradually filter into the ground where they can do less damage. Therefore, we thought it was important to find the driveway material that had the highest rate of permeability for our community to use.

Our group brought in a hermit crab tank and made material blocks out of concrete, gravel, concrete with embedded gravel, and driveway repair, which simulated porous asphalt. Porous asphalt allows some water to go through and was a possible contender for the most environmentally friendly driveway.  After school we cut out the bottoms of tupperware, replaced it with mesh, and put the samples of each material in them. We placed the container over the fish tank and poured 500 mL of tap water through. We waited for three minutes and then took the container off of the tank. We then measured the water that had collected in the tank and were able to determine how much passed through the surface. Here were our results:

 

 

Type of Material Starting Amount of Water (mL) End Amount of Water
Trial 1 (mL) End Amount of Water
Trial 2 (mL) End Amount of Water
Trial 3 (mL) Average End Amount of Water (mL) Concrete 500 58 82 61 67 Concrete/ Gravel 500 80 87 82 83 Gravel 500 397 450 445 431 Driveway Repair (Simulates Porous Asphalt) 500 458 461 475 465

In this table you can clearly see that gravel and driveway repair, simulating the porous asphalt, allowed the most water to permeate and are the best choices for a driveway. You can also see that the concrete and concrete/gravel mix are bad choices for driveways as they leave most of the water sitting on top of them. This will cause cracks and have a negative impact on local ecosystems. We hope that learning this will help you make the better choice for your driveway in the future.