Materials: Mixing Water for Concrete
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> Materials: Mixing Water New ASTM Specification
for Mixing Water
 ASTM
C 1602, Standard Specification for Mixing Water Used in the
Production of Hydraulic Cement Concrete, defines sources of
mixing water as:
- Batch water. Batch water discharged into the
mixer from municipal water supply, reclaimed municipal water,
or water resulting from concrete production operations. This is
the main source of mixing water in concrete.
- Ice. During hot-weather concreting, ice may
be used as part of the mixing water. The ice should be completely
melted by the time mixing is completed.
- Water added by the truck operator. ASTM C
94 (AASHTO M 157) allows the addition of water on site if the
slump is less than specified, provided the maximum allowable water-cement
ratio is not exceeded and several other conditions are met.
- Free moisture on aggregate. Free moisture
on aggregate can represent a substantial portion of the total
mixing water. It is important that any water brought in by the
aggregate be free of harmful materials.
- Water contained in admixtures. Water contained
in admixtures must be considered part of the mixing water if the
admixture’s water content is sufficient to affect the water-cementitious
materials ratio by 0.01 or more.
Recycled Water
Non-potable water and water resulting from concrete production operations
can be used as mixing water in concrete provided the acceptance
criteria given in ASTM C 1602 are met. Water recovered from processes
of concrete production includes: (1) wash water from mixers or that
was a part of a concrete mixture, (2) water collected in a basin
as a result of storm water runoff at a concrete production facility,
or (3) other water that contains quantities of concrete ingredients.
The solids content in recycled water generally ranges from 2.5%
to 10%. The maximum permitted solids content for water to be used
in concrete is 50,000 parts per million, or 5%, of the total mixing
water and should be tested in accordance with ASTM C 1603.
The National Ready Mixed Concrete Association has summarized the
issues involving the revised mixing water requirements and use of
the new standards. Click
here to download the document.
Contact ASTM International, 100 Barr Harbor Drive, West Conshohocken,
PA, 19428-2959, Phone: 610.832.9585, or www.astm.org,
for ordering standards.
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