Staff writer
(Editor’s Note: This story is about the people constructing and the product being used at the new sewer lagoons at Hillsboro. In a future edition, there will be a story about the lagoon project and its functions.)
Many have heard the slogan, “Shop At Home” or “Keep the Money Local.”
When the City of Hillsboro decided to move forward with its new wastewater treatment facility, the spirit of hiring and spending locally must have held true because two of the sub-contractors are located in Marion County.
Three lagoons or cells are being constructed east of Hillsboro to meet the future needs of the community.
The general contractor of the multi-million dollar project is APAC-Kansas, Inc. with Evans-Bierly-Hutchison & Associates P.A. providing engineering expertise.
Hett Construction of Marion is the concrete sub-contractor with the concrete coming from Concrete Products Inc. of Hillsboro.
When the project was designed, it was decided to use a fiber mesh in the concrete instead of all steel.
The fiber mesh is distributed by Synthetic Resources of Peabody.
Fiber mesh is a product that has been put in concrete products for some time.
According to David Liefer, the product is specifically called Fibernet Concrete Fibers and comes in one and one-half-pound water soluble paper bags. The entire bag is put in the cement product. As the product mixes, the bag with the polypropylene breaks down and dissolves, leaving the plastic product as the only additive.
Typically, one bag of the product is used per yard of cement. For this particular project, two bags or three pounds were used to provide additional stability and strength. Most importantly, the fiber mesh additive reduces plastic shrinkage cracks in the concrete. These shallow cracks occur when water evaporates from the surface of freshly-placed concrete faster than it is replaced by bleed water.
Although unsightly, typically they do not require any type of repair.
For Davey Hett, owner of Hett Construction, this is the first time he’s worked with the plastic product in concrete.
Since his crew started working at the lagoon site, the weather has been hot with temperatures in the 90s most days, peaking to near 100 other days.
In an effort to stay ahead of the cement drying too quickly, Hett and his crew of 15 men begin their day at 4 a.m., shutting down before the temperature gets too hot to spread the concrete mixture.
And so did employees of Concrete Products. They were at work by 4 a.m. to have the cement ready to be poured when the construction company called.
The walls are a 3:1 slope, which is the same as a 4:12 pitch on a roof — quite steep.
Concrete footings are at the base of each section to keep the cement from sliding down the hill.
One of the reasons for the fiber mesh, Hett said, was the acid in sewage won’t eat through the fiber mesh like it could steel.
When the job is finished, there will be 2,650 yards of four-inch concrete. The walls are 19 feet long and 25 feet deep.
For inspector Jamey Stapleton of EBH, this is the largest lagoon project he’s done.
“They’re getting the state-of-the-art,” he said.
Jim Kohlman of EBH is the project engineer.
“This system was sized for the city, 20 years down the road,” he said.
Using fiber mesh is labor-saving, keeps project costs down, and should work as well as steel.
So, when do contractors use fiber mesh?
Kohlman said typically the product is used for sidewalks and other projects that are not structural or driven on by heavy vehicles.
Jeff Schmidt, manager of Concrete Products of Hillsboro, said his company has used the fiber mesh product before but not in a project like this.