Recycling Gets Concrete
Virginia's Department of General Services recently brought down an old, unwanted, state-owned laboratory building in Richmond in preparation for the construction of a new parking garage. Departmental planners and engineers were interested in the possibility of reusing construction debris. However, recycling was not mandated by state regulations, so they were careful to implement a process that would ensure a net savings to taxpayers.
For instance, they took care to include materials recycling in the construction request for proposals (RFP). They realized that the demolition would take longer than normal because of the need to separate materials on site.
Early on, the engineers had decided that faster demolition, using implosion methods, would not be an option in this case. The old building was not tall enough so that its collapse could be controllable. Furthermore, concerns about dust, noise, and vibration in adjacent office buildings led to the conclusion that a gradual demolition and sorting of materials should occur simultaneously.
The "biting" and crushing of the building structure was done with a Caterpillar 330 B heavy front-end loader. The old building's basement was temporarily filled with debris to create a platform to allow the equipment to reach the upper levels.
All 14,000 tons (13 million kilograms) of concrete, asphalt, and metals were sorted for recycling as demolition progressed. Everything except the concrete was sent to specialized recycling facilities.
It was found to be more practical and less expensive to bring a concrete crusher to the site than to haul the 12,750 tons (12 million kilograms) of concrete elsewhere to be crushed. The crusher broke the concrete into pieces of a size that could be put back into the ground as backfill for the new construction. A conservative estimate is that more than $485,000 was saved through recycling and reusing materials on site.
Engineers at the Commonwealth of Virginia Department of General Services hope to set an example by this project and to continue to include similar recycling requirements in future RFPs, thus saving money while helping the environment.
More information about construction- and demolition-debris reduction is available from the U.S. Environmental Protection Agency.
Discuss this article in the Architecture Forum...