On a recent trip to visit my daughter at college, we took in a concert at the outdoor amphitheater.  The band was not that good, but I was very intrigued by the stone work that comprised the main stage and aprons.  From a distance, it appeared to be constructed of natural field stone as the colors varied throughout the facing. However, upon closer inspection, I found it to be recycled concrete. Now I have seen concrete re-purposed before, in fact a classic example lies at Callaway Gardens in the Sibley Horticultural Center.  But the difference there is that the concrete is mixed with real stone to give a much more natural look.  In the amphitheater example, pictured, the walls are completely comprised of broken pieces of concrete. The look comes off as a cross between natural stone and manufactured segmental wall blocks.

The ecological benefits of using recycled concrete are huge. Since concrete is one of the world’s most popular building materials having a lifespan of 50-75 years before needing to be replaced, the importance of keeping old concrete out of our landfills is paramount.  Additionally, by recycling an existing concrete surface, you eliminate the need to manufacture new concrete material for your wall project, thus eliminating transportation/fuel costs, gravel mining, and water usage.

Recycled concrete walls are constructed by using broken up pieces of concrete mortared together to create a wall that uses its own weight for stability.  When constructed, the base will be wider than the top and the wall should angle back into the slope slightly. This type of wall is considered a mass gravity wall and is one of the earliest types of wall construction.  Have you ever seen pictures or visited a site that had old walls outlining the fields?  These are typically mass gravity walls.  The character and charm they create is wonderful and can be imitated quite cost effectively using recycled concrete.

Constructing recycled concrete walls makes the most sense when you have a source for the concrete readily available.  Keep your eyes out for neighbors replacing driveways or contact contractors who may relish the idea of offloading their debris with you. Better yet, if you can recycle the concrete you already have on site; its carbon footprint is drastically reduced.