More recently a third type of aggregate has emerged: recycled concrete aggregate (RCA) which is produced by crushing concrete reclaimed from demolished highways, buildings and other structures.

Aging infrastructure, scarce landfill space, cost savings and environmental benefits all fuel the growing demand for concrete recycling.

Concrete from demolition sites is crushed, processed to remove metal such as reinforcing steel, and then screened to appropriate sizes. The crushed concrete is then re-used as aggregate for fill, road base or even new concrete – many of the same applications as conventional crushed stone.

There are two approaches to recycling concrete. One approach is to haul the concrete debris to a permanent recycling facility or quarry for crushing and screening.  The alternative is to crush and screen the material at the demolition site. Using portable crushers on site reduces construction costs and eliminates the need to transport the material to and from a quarry or recycling facility. Transportation costs, energy use and wear and tear on roads and equipment are all reduced. The recycled aggregate is used as soon as it is processed.

Recycled concrete currently supplies about 5% of aggregate use. The bulk of recycled aggregates – about 68 % – is used as road base. The remainder is used for new concrete mixes (6%), asphalt (9 %) and fill.

Recycling concrete features both cost savings and environmental benefits:

• Reduced disposal of concrete in landfill
• Conservation of natural resources
• Reduced cost for raw materials
• Energy savings from less processing and transportation