What is Recycled Concrete Aggregate?
Recycled Concrete Aggregate (RCA) — also called “crushed concrete” — is made up of asphalt debris from other construction projects that can be reused to create driveways, pathways, garden beds and more.
When any concrete structure, road, sidewalk or parking lot is destroyed, that concrete is often deposited in a landfill. Concrete is not biodegradable and unfortunately, will not decompose. Rather, it sits there taking up space and causing environmental problems. At the same time, new concrete is being created to begin the process all over again.
There is a solution to this wasteful, expensive cycle. It’s recycling!
Recycling crushed concrete to be reused helps reduce landfill crowding AND saves more resources from being used to create new concrete. Old concrete can be crushed down to specific sizes, cleaned so that unwanted debris is removed from the mixture, and reused as a solution to a number of construction and landscaping problems.
US History of Using Crushed Concrete for Roadway and Driveway Construction
Since the 1940s, recycling concrete pavements (crushed concrete) has been a fairly common solution. The first instance in the US was following World War II. US Route 66 in Illinois needed to be expanded from two to four lanes. During this reconstruction project, the old concrete was recycled and reused in the new project.
Later, In the 1970s there was a big push to reduce landfill overflow. Crushed concrete became a more and more popular material choice for both roadways and driveway construction. Crushed concrete continued to grow in popularity into the 1980s along with recycling efforts.
What kinds of Concrete can be Recycled into RCA?
Concrete from many different applications such as old concrete structures, sidewalks, building slabs, foundations, curbs, and more can be recycled into RCA.
How is Concrete Recycled?
The first step to recycling old concrete is to use industrial crushing equipment in order to break up the original structure. Next, the broken up concrete is run through a secondary impactor. After being crushed to an even smaller size, the crushed concrete is then screened so that dirt and other foreign objects can be removed. After this step, the concrete is separated out by size.
Another method for recycling concrete is pulverization. Pulverizing the concrete isn’t the best way to recycle concrete, however. It can make the separation of contaminants much more difficult, lowering the quality of the finished RCA.
When concrete is recycled, it can be broken down into a variety of sizes. Each of these sizes is well-suited to different applications, making the material incredibly versatile.
Large pieces of RCA, for example, can be used to create “rip-rap.” Rip-rap, sometimes referred to as riprap, shot rock, rock armor, or rubble, is larger slabs of recycled concrete used along shorelines to control erosion or form a breakwater. Smaller gravel bits of RCA are often used as a sustainable, affordable subbase for roads. Dry aggregate can even be reconstituted as new concrete.
What kinds of projects can be done with Recycled Concrete?
Base for Asphalt Parking Lots and Roads
Smaller-sized RCA can serve as a stable, reliable base for asphalt parking lots.
Walkways / Pathways
Crushed Concrete can be reused to create walkways in your landscaping. Make sure that you’re using uniform RCA pieces for your walkway. This will help prevent rainwater from causing runoff and drainage issues. Uniform pieces also make the finished walkway more visually appealing.
Raised Garden Beds/Landscaping
Creating a raised garden bed provides a lot of benefits. Some of these include improved drainage and warmer soil, both of which lead to faster growth for your garden when spring comes. To create a raised garden bed, lay crushed concrete in layers. This will form the perfect base.
Larger pieces of RCA are perfect for creating retaining walls or rip-rap to help control erosion or create a breakwater. Different sizes of crushed concrete can function together to help prevent erosion. A layer of smaller, more broken-up crushed concrete as a base will contribute to the stability of the wall. Following with layers of larger recycled concrete packed with dirt will create an even, beautiful retaining wall.
Smaller, more broken up concrete is a great drainage alternative to gravel. We break down how to install a french drain in your landscaping here.
Where Can I Buy RCA near me?
Superior Groundcover provides a variety of RCA sizes, perfect for whatever project you’re looking to complete. Our expert team can help you decide how much material you need, what kind, and even install it for you. Consulting professionals will help you make the right material choice so that you can avoid some of the issues that arise when you pick the wrong size crushed concrete. Some of these issues include erosion and drainage problems.
Another option for purchasing RCA near you is to find a local concrete recycling plant, however we don’t recommend this unless you are a pro yourself and feel confident in the type and amount of the material you will need. You will also need to rent/buy installation equipment depending on the project.
We do have an article to help you out with your DIY crushed concrete installation project here.