|
American
Concrete Products, Inc.
1-800-CONCRETE
Corporate Office
5550 NE 22nd Street
Suite 100
Des Moines, Iowa 50313
Phone: 515-263-3860
Fax: 515-263-3868 |
CONCRETE POPOUTS
The concrete producers of central Iowa and their suppliers consistently produce quality ready mix concrete for a wide variety of applications. However, occasional problems can occur which are beyond the control of the ready mix producer and their suppliers.
Chemical (alkali-aggregate) popouts are sometimes inherent in concrete flatwork
made with the available raw materials in this area. They are caused by
a chemical reaction between alkalies and cristobalite or opaline shale in
the aggregate
deposits. It is impractical to totally remove the compounds that cause
this phenomenon from the raw materials.
It is well established that:
- Local sands comply with
ASTM and IDOT specifications.
- Popouts are most prevalent
in hard troweled surfaces during hot weather, but can occur at
any time.
- Construction
practices can aggravate the problem by increasing the concentration
of
reactive materials at the surface.
- Curing methods can have
the greatest effect on the occurrence of popouts.
Construction techniques can minimize the possibility of popouts occurring. Some of these are:
- Use lowest practical slump.
- Use proper finishing procedures
- Minimize the use of vapor barriers. If they must be used, a layer of
sand should be placed over the barrier.
- Use continuous water curing.
Since the concrete produced locally complies with material specifications of ASTM and IDOT, and because there are circumstances beyond our control, we disclaim any and all responsibility for the phenomena known as "popouts."
For additional information, see the IRMCA fact sheet entitled, "The Alkali-Aggregate Reaction Known as Popouts," or consult your Ready Mix producer. |
|
