Recycled Concrete Aggregate Usage & Benefits
RCA (recycled concrete aggregate) is a cheaper alternative to virgin aggregates and has many uses in the construction process.
RCA (recycled concrete aggregate) is a cheaper alternative to virgin aggregates and has many uses in the construction process.
RCA (recycled concrete aggregate) is a cheaper alternative to virgin aggregates and has many uses in the construction process.
Crushed concrete - also called recycled concrete aggregate (RCA) - is made up of construction & demolition debris. New construction projects often require the demolition of old structures that yield large amounts of broken concrete from demolished buildings, footings, sidewalks, crubs & gutter, ramps, pathways, and driveways. Traditionally, construction & demolition waste has been landfilled or disposed at a centralized recycle yard.
In the simplest form, concrete is virgin aggregate that is glued together with a cement binder. A concrete crusher breaks up chunk concrete and fractionates the material so that you generate a new recycled concrete aggregate product. The cement dust that is generated helps to compact the material nicly and makes a good roadbase. The quality of the recycled concrete aggregate depends on the feed material and the crushing process. The better quality product you produce the easier it is to sell or reuse on jobsites.
Your feed material affects material quality
The cleaner the feed material the more homogenous the end product. If your feed material is mixed with dirt, garbage, and other debris your end product will contain some of the infeed contaminants. Therefore, it is important to manager concrete disposal sites so that inferior product with contaminants is not mixed with clean concrete product. Red brick tends to be an indicator for an inferior recycled product because brick has a lower tensile strength. You can easily spot red brick contamination which makes the material hard to sell.
The cleanest concrete material you can get is washout concrete from ready-mix trucks and rejects from the concrete production process. This material is free from any contaminants and steel and makes a very consistent and high-quality recycled concrete aggregate product.
Recycled concrete aggregate products are 15% to 17% lighter in weight than natural stone aggregates giving you more product for a lower price than natural stone.
Your crushing process affects material quality
Another influencing factor is your crushing process. Recycled concrete aggregate can be produced with a jaw crusher or an impact crusher. A jaw crusher produces a coarse and jagged 3" non-spec material vs an impact crusher is capable of producing a ¾“- DOT spec material.
As quarries, gravel pits, landfills, and recycle yards are pushed out of urban areas concrete disposal becomes a long and costly process. Without turning concrete into a recycled aggregate product contractors face high material and disposal costs and waste time hauling material.
(1) Stockpile concrete
Put concrete in a stockpile and ensure to reduce contaminants by seperating dirty material from clean concrete material.
(2) Preprocess concrete for crushing
Concrete needs to be sized before crushing with a hydraulic hammer or concrete pulverizer. Long strands of rebar need to be cut so that rebar is mostly encapsulated in concrete.
(3) Recycle concrete with a mobile crusher
Produce your own recycled concrete aggregate with either a closed circuit crusher or a mobile crusher with an additional screening plant. The crushing process liberates encapsulated rebar and a magnet segregates rebar to the side.
Recycled concrete aggregate can be used in a variety of applications including:
Sizes and designations vary by state/province due to governing agency requirements.
Ontario, CA | Illinois, USA | New Jersey, USA | Pennsylvania, USA | Florida, USA | |
---|---|---|---|---|---|
Size | 7/8"- | 7/8”- | 3/4"- | 3/4"- | 1½“- |
Spec | Granular A | CA6 | RCA | 2Amodified | B-12 |
Typically, recycled concrete aggregate can be purchased whereever concrete is dumped and collected such as designated C&D recycle yards, landfill sites, quarries, or landscape supply yards. Your local concrete plant might recycle washout concrete which makes a very clean recycled concrete aggregate product.