Launch Slideshow

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All in a Night's Work

All in a Night's Work

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    Four pumps placed the concrete, starting in the center and moving out to all four outside corners of the wall. Thermocouples were embedded to continuously monitor core temperatures.

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    Measuring 168,939 cubic feet and holding more than 800 tons of steel reinforcement, the concrete slab at the Chippewa Falls, Wis., sand plant will support 12 silos, each 70 feet high and 48 feet in diameter.

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    Ready-mix trucks from a variety of producers supplied concrete.

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    A special type of sand is mined in the town of Howard, Wis., which will be processed at the Chippewa Falls plant. Called frac sand, it helps energy companies extract more oil and natural gas.

Quality control at the forefront

Eight days after completing the lean fill placement and with QC personnel making sure there were no problems with the mix, the pour started at 3 a.m. on Dec. 2.

The specifications called for a 4500 psi air-entrained mix containing 428 Type I/II portland cement, 183 Type C fly ash, no water reducers, 1285 natural sand, and 1783 crushed gravel. “We were shooting for 4% air to help pumpability and a 40° F surface temperature to mitigate thermal cracking,” says Steve Lewis. “We embedded thermocouples to continuously monitor and maintain the core temperature at 70° F.”

“From the quality end, team-work was key to our success, as representatives from all three ready-mix companies, Lafarge, and Midwest Engineering Services, which is an independent QC laboratory, were continuously testing and worked closely to ensure a job well done,” says Gary Haas. “We tested the first batch out of each plant and then every 250 cubic yards after that.”

There was a heated enclosed trailer for storing cylinders, which were tested by the independent QC laboratory. QC personnel onsite continuously tested temperature, slump, and air.

R&S Pumping Service used four pumps with a belt placer as backup. With a 60-meter Concord and 58- meter Schwing facing each other and a 45-meter Schwing and 36-meter Putzmeister on each side, R&S hit all the corners of the pour. The pumps never had to wait for trucks and the only backup that occurred was when a pump was being moved.

R&S unloaded 640 yards of concrete in the first hour and averaged between 500 to 600 yards per hour throughout the day. Air temperatures ranged from 8 to 18° F, with concrete temperatures around 40° F. The first boom was washed out by 3 p.m. and the last one two hours later. “At the end, we only called for an additional 16 cubic yards of concrete,” says Lewis.

Key to the smooth operation and completion was the amount of pre-planning, planning, estimating, traffic coordination at the site, and strong commitment to quality.

“Everything that day went as smooth as clockwork,” says Gary Haas. “From an estimating standpoint, it was an outstanding effort on the part of Lafarge to come within 16 yards of the required amount. Rick Borowicz, owner of R&S Pumping, did an amazing job of directing the trucks to specific pumps. Through constant contact with the individual pumpers, a pump never ran out.”

“It was fun to watch the competitive spirit of these dedicated professionals come shining through and it was impressive to see them work together as a unified team,” says Lewis.

It was so cold, Haas Sons brought out a salt truck to treat the main exit off of U.S. Route 53 and the washout area due to ice buildup.

Mike Stolpa is territory sales manager covering western Wisconsin and southern Minnesota for Lafarge North America. For more, visitwww.lafarge-na.com.

[WEB EXTRA SLIDESHOW]: All in a Night's Work
A web slide show tracks the progress as Wisconsin concrete producers work together to complete one large pour.