Can recycled water and non-potable water be used to make concrete?

April 8, 2018

ASTM C94 permits the use of recycled and non-potable water as mixing water in concrete. Such water should comply with Specification ASTM C1602. To qualify these sources of water for use, the water should be tested and qualified. A batch of mortar or concrete is prepared with the test water and compared to one made of tap water, representing the control. The strength of test specimens at 7 days of the test batch should not be less than 90% of the strength of specimens made from the control batch. Additionally, the initial time of setting, measured in accordance with ASTM C403 should not be accelerated by more than 1 hour or retarded by more than 1.5 hours compared to that of the control batch. Additional optional limits are stated in ASTM C1602 on the composition of the water. A test sample is sent to a chemical testing laboratory. Limits are established for alkalis as Na2Oe, chlorides, sulfates, and total solids. Any one or more of these optional limits can be specified by the purchaser when it is important to the structure being built.

Reference NRMCA.org