The construction and demolition industries are making impressive strides toward combating the excessive amount of debris being deposited into landfills. Currently, at least 25% of all solid waste finding its way to landfills comes in the form of construction/demolition waste with concrete debris comprising 70% of that amount. According to the EPA, of the 375 million total tons of annual construction waste, 157.4 million tons comes from road and bridge demolition alone.

As staggering as those figures are, the Construction & Demolition Recycling Association reports that 140 million tons of concrete is recycled each year. With pressure from environmental watch groups, as well as laws/restrictions, concrete recycling has become a mainstream part of construction operations.

What are the benefits of concrete recycling?

• Reduced tippage at landfills

• Reduced freight hauling costs when crushed on-site

• Cheaper aggregate than virgin aggregate

• Reduces construction costs (.25 per mile per ton to haul & $100 per ton to dump)

• Conserves natural resources

• Environmentally friendly practice (reduces air/water contamination)

• Recognized by LEED Green Building rating point system

• Credit awards for 50% diverted waste from landfills by Construction Waste Management

The Varied Uses of Recycled Concrete

So what and how do companies handle the concrete waste from their demolition sites? These are some of the common markets for recycled concrete:

Airport Runways

Erosion Control Structures (i.e. gabion cages)

Gutters

Building Foundations

Add a portion of recycled aggregate to virgin aggregate in new mixtures

Underpass Abutments

Top Use: Base Course (Road Base) for new roadways

Pipe Bedding

States Put Recycled Concrete To Good Use

According to the Portland Cement Association, a recent FHWA study found 38 states are using recycled concrete as an aggregate base and 11 states are using recycled concrete in new portland cement with equal performance reporting. In one case study conducted in October 2009 at the Chicago O’Hare Airport, two new runways were constructed side-by-side. One lane was constructed of completely virgin aggregate. The other lane was constructed with a mix of recycled concrete/virgin aggregate. Sensors were placed to record data. After five months of monitoring, both lanes were recording statistically that same results.

The Process

The process of recycling concrete is relatively simple. With five steps, it’s a relatively easy process to follow to reduce not only environmental impacts, but also increase cost savings.

There are a variety of concrete recycling machines that can be used to recycle concrete either on-site or at a recycling facility. Crusher attachments for heavy equipment can crush 100 tons per hour, mini-crushers can crush 150 tons per hour, and road portable crushers can crush over 600 tons per hour.

Conclusion

It makes good sense and good “cents” to protect both the environment and the bottom line of construction and demolition by incorporating concrete recycling into job operations.

PCI Gulf South certified producers take protecting the environment seriously. Few industries are as focused on moving towards sustainable solutions as the precast concrete industry. Precast is not only a durable solution, it’s one that contributes to sustainable design in a multitude of ways.