RECOVER® as Wash Water Treatment – TB-1300
Effect on Concrete Performance
The stabilization of the Portland cement hydration process by RECOVER® is not permanent and is controlled by dosage rate. A very useful equipment maintenance application for concrete producers is the use of RECOVER® as a wash water treatment.
The RECOVER® treated wash water is mixed or sprayed so as to thoroughly coat the interior of the mixer. The water is used as mix water in the next batch of concrete produced, which then scours the unhardened material from the interior of the mixer.
Throughout the field development and testing of RECOVER® as a wash water additive, the effect on concrete performance was monitored.
A tremendous range of mix designs, materials and conditions were studied, and in each case, the RECOVER® treated wash water had no adverse effects on the properties of the concrete produced.
Generally, the following was observed:
| Property | Effect |
|---|---|
| Initial set | ± 1 hour |
| Air content | ± 1% |
| 1 day strength | up to 3.4 MPa (500 psi) increase |
| 7 day strength | up to 3.4 MPa (500 psi) increase |
| 28 day strength | up to 3.4 MPa (500 psi) increase |
| Finishability and pumpability | none |
The only substantial trend observed was a moderate increase in strength. This increase is attributed to the cementitious contribution of the wash water. Essentially, RECOVER® treated wash water (which is typically high in cementitious and fine material) simply acts as a coating for the mixing drum.
