EVERETT – Everett Public Utilities employee Paul Crane was so excited about a new type of environmentally friendly concrete that he bought some and tested it in his backyard.
The results impressed him.
The concrete absorbed water and then allowed it to pass through to the soil below. Crane also learned that the concrete can lessen flooding problems and limit runoff of environmentally harmful materials such as oil into local waterways.
Crane’s backyard experiment led the City Council last week to approve spending $280,000 on a new parking lot at the city’s water-filtration plant on Smith Island that will use this concrete mix called Perco-crete.
The city’s parking lot paving job will be the largest project in the United States using Perco-crete.
The parking lot will have 28 spaces and will replace spaces lost by a water-filtration plant expansion. The city will monitor the lot in the months after it is built this summer and decide whether to use Perco-crete on other projects, Everett Public Utilities director Tom Thetford said.
The lot will cost about $60,000 more than it would have had regular concrete been used, Crane said.
Thetford said the city may recoup at least some of the cost by not having to build drainage pipes and catch basins to collect water from the site.
Instead, Thetford said, “it will put water into the ground as would occur naturally.”
Perco-crete has been used in Japan for several years, said Frank Michiels, president of Michiels International, Inc., which imports the product. Perco-crete looks somewhat like ash and is added to regular concrete mix, he said.
One day last year, Crane, a landscape architect with Everett, drove to Michiels’ office in Kenmore to talk about the product. Crane was following up on what a fellow city employee had heard about Perco-crete at a public-works conference.
Crane bought a 1-pound sample for a few dollars and mixed it with an 80-pound bag of standard concrete mix. After seeing how well it worked, he convinced Thetford to back the project.
Perco-crete isn’t the first concrete that uses porous material to direct water into the soil. But it works much better than standard porous concrete, said Craig Tosomeen, project engineer for the city of Olympia.
Olympia built sidewalks in 1999 with regular porous concrete. But standard porous concrete is costly to maintain, he said.
“Leaves, litter and pine needles get into it,” Tosomeen said. “It’s hard to clean out. And you need to clean it out to keep the pores unclogged.”
Last summer, Olympia built 50 feet of sidewalk out of Perco-crete, to test how it works. It’s smoother, so leaves and litter don’t clog the pores, Tosomeen said.
Olympia officials were so impressed by Perco-crete that, over the next several years, 80 percent of the city’s $1 million in new sidewalks each year will be built with it, Tosomeen said.
Reporter David Olson: 425-339-3452 or dolson@heraldnet.com.
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