Value Of Concrete Recycling

What Do You Do When The Landfill Is Full?

There is enormous pressure on local governments to maintain and control the utilization of landfills. One major issue relates to used concrete which is routinely dumped for disposal. However, concrete recycling is gaining in popularity as the preferred method to transform rubble into a valuable resource.

Concrete consists of cement, sand and a variety of coarse aggregates. In addition, concrete demolition frequently uncovers steel bars commonly used for structural reinforcement, which can be segregated from the aggregate through the use of magnets.

A series of actions are required in order to produce an acceptable concrete recycle. Cost efficiency dictates that whenever possible crushing should occur at the actual construction site using portable equipment. Depending on the size of the job it might be feasible to utilize compact, self-contained mini-crushers that can handle up to 150 tons per hour and are able to fit into close quarters.

Extensive cleaning is required to ensure the recycled concrete product is free of dirt, clay, wood, plastic and organic materials. This is done by water floatation, hand picking, air separators and electromagnetic separators. Sometimes asphalt overlay or patch is found and this should be separated to the greatest extent possible.

There are many efficient uses of recycled concrete to include riprap or rock armor, which is used to line shorelines or stack against bridge abutments to provide support and help reduce water or ice erosion.

Smaller pieces of concrete can be used as gravel for a variety of new construction projects. In fact, the roads you drive on today might have a sub-base of recycled concrete gravel as the first foundational layer before asphalt has been poured over it.

In addition to providing relief to our landfills, aggregate that has been properly recycled is high quality and provides for superior compaction and constructability. Its higher yield means less weight per cubic yard, which reduces material costs, hauling costs and overall project costs.

Recycled aggregates are typically on a par with conventional aggregates, unless, of course, the original concrete was of poor quality. Recycled concrete can be batched, transported and placed exactly like conventional concrete. But, special attention is called for when using recycled fine aggregate, which should be tested to determine the optimal rate.

It is worth noting that the full-depth reclamation (FDR) for recycling roads in the U.S. relies heavily on the use of recycled concrete in addition to the old asphalt and base materials which are pulverized to produce a strong durable base for either an asphalt or concrete surface.

As standards continue to improve, more contractors are being educated and encouraged to incorporate concrete recycling into their operations. Certainly the ability to decrease disposal costs is gaining attention as more sites are opening up. This is especially true when recyclers are able to move portable recycling machinery to the plant site.

When concrete is recycled energy is saved compared to mining, processing and transporting new aggregates. And while not considered environmentally damaging, the large volume of concrete waste generated during demolition makes it difficult for landfills to accommodate.