FOR MOST RESEARCHERS, the end of a major project means it's time to finally take a deep breath, decompress, and consider the next major effort. But for Kurt McMullin, finishing his research project, Defining the Drift Sensitivity of Precast Cladding Panels Under Static Seismic Loading, was just the beginning of another quest.
When applying for the federal funds for the research in 2005, McMullin, associate professor in the Department of Civil Engineering and Applied Mechanics at San Jose State University, wanted to find an alternative use for the concrete he would use in the testing. “Typically, when we finish a test like this, we just scrap the panels and they are probably ground up and end up in a landfill,” he says. “So when we asked for the federal money, we added a line item that one of our goals was to find a different use other than simple disposal.”
Precast producers told McMullin that when they have production errors or when a panel has a defect, they save some of the steel connections, but the remaining piece is pretty much a total loss. That seemed to be a waste.
The parts of the panels which were badly cracked during testing were cut off and the remaining pieces were sent to a jobsite. The original panels were 16 feet by 4 feet by 5 inches. The crew at the jobsite was replacing a cast-in-place slab at an outdoor recreation center for a youth facility.
“They were trying to tie these panels together to make a single unit to cover the whole area, but it was getting too complex and expensive, so they finally had to dispose of the panels,” McMullin says. He isn't sure of their final resting place. Usually in California, they are ground into aggregate and any steel that is reclaimed is recycled.
The experience caused McMullin to think of a better way to find alternative uses for precast concrete that maybe be damaged or defective. At the Precast/Pre-stressed Concrete Institute Convention this fall, McMullin gave a presentation on the subject and found other precast producers wondered the same thing.
“They have a certain amount of material they need to dispose of and they would like to find an avenue for,” he says. “It's a matter of identifying who is a good consumer for it, and also educating the consumer on how these could be used.”
McMullin wants to learn from pre-cast producers how much of this sub-quality material they usually have. He believes a big consumer like the U.S. Department of Agriculture might be interested in taking it off their hands. Producers told him farmers ask for large pieces of concrete that is waste. They often place them in fields as foundations for fuel tanks.
He originally considered photographing the pieces, supplying documentation, and posting the information on the eBay auction site. But McMullin favors a more formal procedure. This would include identifying the source, the amount available, and describing the defects, such as aesthetic damage versus actual cracking.
McMullin is not sure producers could charge for these pieces. But if it means they would not have to pay disposal costs, they should find this effort worthwhile.
Finding homes for defective precast concrete is probably already occurring on a case-by-base basis, but McMullin wants to see a more formal process in place. “If there was some coordination and especially with the Internet and the ability to move information quickly, this has great potential,” McMullin says. He would like to hear producers' ideas. E-mail firstname.lastname@example.org, or telephone 408-924-3855.