Civil engineering researchers at Purdue University are currently trying to perfect a process for the handling and reuse of recycled concrete. It is believed that recycling concrete could help reduce construction costs by 20%, and cut down on resources (such as limestone) from being quarried. Working with the Indiana Department of Transportation (INDOT), the process is being evaluated and tested for eventual use in highway construction.
The recycled concrete would be used to replace the local “virgin aggregate” which is added to cement, water and sand to make paving concrete. Generally, rock such as limestone is brought in from a local quarry, but this process can prove more difficult in areas without such resources. Using crushed recycled concrete would allow construction companies to mix concrete pavement, regardless of the proximity of quarries.
“Repaving requires uprooting existing concrete, so instead of putting the old pavement in landfills, recycling just makes sense,” said Jane Olek of the Joint Transportation Research Program. If used, the recycled concrete could reduce the cost of paving materials by 10-20 percent – not to mention it would cut waste, and waste removal costs.
The researchers are experimenting with the optimal ratio of recycled materials in the concrete mixture to ensure durability and safety, as well as to begin to set a standard for the reuse of old concrete. Currently, 400 different combinations are being produced and tested for things like water absorption, freezing and deicing chemicals.
INDOT and Purdue plan to have a report by early 2012 which will list recycled concrete aggregate combinations and durability