concrete recycling 1

[gracemui]

Is it possible to use water effluent, resulting from the process of concrete recycling (at batching plants), to manufacture fresh concrete?

Is there any specific requirements on the water used in the making of concrete?

Which are the countries that allow for the partial replacemnet of potable water with such recycled water?

 

[Ron]

While it is desirable to use potable water for concrete production, it is not absolutely necessary. The key is to have water that is not deleterious to the process of hydration or long-term durability of the concrete. For that reason, organic compounds and soluble chlorides are usually excluded from water for concrete production. An exception to this is that seawater has been used many times for successful concrete production; however, the corrosion of rebar or embeds is much higher than with potable water.

Assuming no deleterious materials in the wash water, and mostly containing calcareous materials and grit, the water can likely be used for concrete production. Have it checked for organics and chlorides or other contaminants, but it should be OK.

 

[krd]

Gracemui, Washington State DOT allows water from mixer washout at a batch plant to be reused in some concrete. Might be similar to other process water. No recycled water is allowed in concrete for bridge decks, overlays or precast.
Requirements are; meet ASTM C94 table 1&2; SG less than 1.07; alkali less than 600 ppm; no coloring; certify that admixtures are from same manufacturer or do compatability tests; test all above monthly using AASHTO R-18 qualifications.