Concrete may seem like a wasteful product to many. It’s great as a construction material, but if a building is demolished, all we see is a wrecking ball tearing into a wall and pulverizing the concrete into tiny bits. It may seem like there’s not a lot of reuse for this garbage, but researchers at the University of Southern Denmark are flipping this perception upside-down.
Since March 2013, researchers in that school’s biology department have been testing the ability of used, crushed concrete to remove phosphorus runoff from water. Phosphorus is used heavily in fertilizers across America. Rainwater can pull this phosphorus away from the soil and into waterways, where it can feed the growth of algae. Too much algae can deplete the oxygen in an aquatic environment, reducing the amount of life that can thrive underwater.
What those from the University of Southern Denmark have found is that when water containing phosphorus is sent through a filter of crushed concrete, the chemicals in the filter bind up the phosphorus and remove it from the water. Cement, a major component of concrete, contains calcium, aluminum and iron, each of which easily binds with phosphorus. Finely crushed concrete is capable of removing up to 90 percent of phosphorus from water running through it.
The experiments in Denmark have only been going on for about half a year, but researchers believe that a crushed concrete water filter can last for a period of several years. One issue is the high alkalinity of water once it passes through the concrete. Once the water has been cleaned, the pH balance rises to a level where it is unsafe for aquatic life. However, adding some acidity to the water to even out the pH level is possible, and it’s usually only required for the first six months of filter service. Once the filter has used up its binding capability, it can then be used for filler in road paving projects.
There is no such thing as wasted concrete. BergenMobile Concrete understands that the future of the concrete industry has big implications for the future of a sustainable world.