Concrete Recycling Most Recently, Both

Concrete Recycling

Most recently, both companies and consumers have begun to recognize the importance of "going green," with recycling. Being able to use the same products helps the earth and can save considerable money, time and manpower. Concrete recycling is increasingly becoming a common method of disposing of broken up structures and roads. The article, "Former Stapleton Airport recycled and revitalized," demonstrates how much can be done with this reused concrete.

In 1995 Stapleton International Airport in Denver, Colorado, was over 65 years old and one of the busiest airports in the United States. Its concrete runways and concourses sprawled over the outskirts of the city. When the airport was replaced by an ultra-modern International facility, the city began selling the millions of tons of dug up concrete instead of dumping it at some landfill for infinity. The concrete being recycled comes from 975 acres of runways, taxiways, service drives, and aprons with an average thickness of two feet.

This decision "killed two birds with one stone" as the saying goes. First and foremost, it reduced the impact on finite resources. Second, the versatility and high-quality of the concrete can and has since been used in the new airport as well as a variety of other ways by a host of developers. The concrete has been readily recycled and reformed into many different structures, such as roads, sidewalks, bridges, curbing materials, offices, retail centers, homes, and hospitals. The flexibility of the material has especially been an important factor in the renaissance of the Stapleton airport site. Soon after the old airport landed its last plane, construction started on a huge mixed-use development, which included commercial space, energy efficient homes, and schools.

Recycling such material is definitely a big plus for the world, and what they did in Colorado is an example that should be followed whenever large amounts of concrete are being broken up. Apparently, the strength of the concrete is also holding up (pun intended). Tests have been conducted to compare 100% virgin aggregate and varied percentages of recycled materials. The results are that some recycled materials are equal to or, in some mixes, even superior to 100% virgin aggregate. According to recycling specialists, recycling of concrete is a relatively simple process. It consists of breaking, removing, and crushing existing concrete into a material with a specified size and quality. It is overall agreed upon that when natural sand is used, as much as 30% of natural crushed coarse aggregate can be replaced with coarse recycled aggregate without significantly impacting any of the mechanical properties of the concrete. However, replacing higher amounts will result in increased drying shrinkage, while strength and freeze-thaw resistance are not significantly affected.