Concrete Recycling is Becoming More Popular for Many Reasons:Concrete recycling is much more viable than it used to be due to high landfill costs, the expensive cost of trucking old concrete to the landfill, environmental concerns, and the advent of recycling machinery. Demolition work includes provisions for recycling concrete much more often nowadays. The benefits of recycling concrete far outweigh the risks, and it looks as if the practice will continue to become more common in the near future. The recycling of concrete involves some fairly large machinery. The main piece of machinery is a crusher that crushes up large blocks of unwanted concrete into small pieces, which will fall onto a screen. Pieces that are small enough to be "harvested" fall through the screen mesh, and larger pieces are re-routed back to the crusher to crush them into smaller pieces. The other main piece of machinery is basically a big magnet to remove rebar and other metal grid-work that may be inside the concrete. Concrete that is free of foreign objects is easy to recycle, and having large magnets to remove the rebar is safer and easier than doing it by hand. Concrete crushers and magnets may be mobile or stationary. With the popularity of concrete recycling and re-use on-site, mobile crusher systems are becoming more common. Some can crush up to 600 tons of concrete per hour. Mini-crushers are self-contained units that can crush up to 150 tons of concrete per hour while fitting into a much smaller area. Crusher attachments, such as conveyors and magnets, are making the popularity of mini-crushers increase rapidly. While they can "only" handle 150 tons per hour, for concrete that is to be recycled on-site, they're perfect. Recycled concrete is most often used as sub-base gravel in new construction projects. This is the lowest layer put down when a new road is built, and fresh concrete or asphalt is poured over top of it. Crushed concrete also works as dry aggregate for new concrete. If the crushed concrete is free of contaminants, it can be used as-is in the form of dry aggregate. Sometimes, however, virgin aggregate is combined with recycled, crushed concrete for making new concrete. Large pieces of crushed concrete can be used for control of erosion, and finely ground concrete can sometimes be used as landscaping stone. Retaining walls and privacy fences can be made from stacked cages filled with crushed concrete. Disposing of concrete in a landfill is becoming expensive enough to encourage recycling efforts. Additionally, the use of recycled crushed concrete as aggregate on-site can save 50 to 60% over the costs of using new aggregate. Downsides to recycling concrete are hard to come by, but one concern has been effects of lead in painted concrete. The Army Corps of Engineers made studies of lead-based paint in crushed concrete, and they concluded that crushed concrete containing lead-based paint could be used as clean fill as long as it had at least a soil covering. Impervious cover over crushed concrete is even better. Even concrete containing lead-based paint can be re-used as long as it has soil or impervious covering over it. Recycling old concrete on-site during demolition/rebuilding projects cuts costs even further. Concrete recycling from small DIY projects is gaining popularity too. The cost of either hauling the old concrete to the recycling facility or having the recycling company collect the old concrete will often be significantly less than the cost of landfill fees. The cost savings and lower environmental impact of recycling concrete over putting it in a landfill (then starting over with brand new concrete on-site) is causing the feasibility and popularity of concrete recycling to increase greatly, and the practice is expected to be adopted widely in coming years. If you have any questions on concrete recycling methods, please feel free to send me an email. Meet-Mr-Concrete.com provides concrete construction advice at no charge and in good faith for consideration only. We do not warrant the implementation of its content and are to be held harmless when and if any advice or ideas provided are utilized. The risk from using it lies entirely with the user. 
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