Eliminating Swirls in Precast Panels Maspeth NY

What can we do to eliminate swirls in precast panels? Sid Freedman of the Precast/Prestressed Concrete Institute says such swirls are signs of segregation caused by the placing method. Read on to know more.

Local Companies

North Shore Hardware
(718) 981-1013
647 Forest Ave, Staaten Catering
Staten Island, NY
Lowe's
(718) 682-9027
2171 Forest Avenue
Staten Island, NY
TANNER BOLT & NUT CORP
(718) 434-4500
4302 Glenwood Road BROOKLYN, NY, 11210
Brooklyn, NY
The Home Depot
(516)488-8500
600 Hempstead Turnpike
Elmont, NY
The Home Depot
(914)963-3003
601 South Sprain Rd
Yonkers, NY
Monster Woodshop
888-506-6678
607 18th Street
Brooklyn, NY
Tsigonia Paint & Hardware
(201) 435-0979
464 Communipaw Ave
Jersey City, NJ
Fastenal- Oceanside
516-764-1013
104 Mott St Oceanside, NY, 11572
Oceanside, NY
Nunez Depot
718-665-8380
2756 3rd Avenue
Bronx, NY
The Home Depot
(718)818-9334
545 Targee Street
Staten Island, NY
Data Provided by:
  

Source: THE CONCRETE PRODUCER/CONCRETE JOURNAL MAGAZINE
Publication date: December 1, 1998

We produce precast exposed-aggregate sandwich panels using concrete made with Type III cement, a 0.38 water-cementitious materials ratio and enough superplasticizer to achieve a 7- to 8-inch slump. The forming bed is made of wood. Using a bucket that passes down the center of the bed, we pour enough concrete for a 3-inch-thick layer and rake the concrete to the edges. We consolidate that layer with an immersion vibrator, then screed it off before adding a 2-inch-thick insulation board and 3 more inches of concrete.When we sandblast the formed panel surface to expose the 1/2-inch limestone, the limestone particles appear in groups or swirls. What can we do to eliminate this problem?

Sid Freedman of the Precast/Prestressed Concrete Institute says such swirls are signs of segregation caused by the placing method. You should place concrete on top of concrete in successive bucket passes because blending separate puddles or passes of concrete creates areas that are heavy in mortar. Raking can cause a similar problem.Ed Boyle, plant manager at Lombard Architectural Precast, Alsip, Ill., suggests using a placing bucket with a wider-than-normal gate, then overlapping each successive pass to eliminate paste streaks.He also suggests using a vibrating screed that hangs off of the form side rails at the correct depth to consolidate your first layer of concrete.

Click here to read full article from The Concrete Producer

Related Articles
- Fan-Fold Foam Board Maspeth NY
Fan-fold foam board is widely marketed as an easy fix for improving the thermal performance and water resistance of walls when re-siding. But if not applied properly, this option could lead to moisture problems, according to leading building-science experts.
- Eco-Friendly Products Maspeth NY
- In Style with Tile Maspeth NY
- High-Efficiency Products Maspeth NY
- Home Exterior Product Reviews Maspeth NY
- Hand Tools Maspeth NY
- Flashing at Sills Maspeth NY
- Home Exterior Products Maspeth NY
- Flue Liners for Masonry Chimneys Maspeth NY
- Eco-Friendly Product Reviews Maspeth NY