SUITABILITY OF WATER FOR CONCRETE MIXING

OBJECTIVE

To assess suitability of water for use in concrete mix.

Equipment

• Measuring cylinder
• Cube moulds
• Trowel
• Tamping rod
• Vibrating table
• Testing machine

Procedure

1. Analyse water for its chemical compositions as per IS 3025-1964 and compare these with permissible limits given in IS: 456-2000.
2. In case water does not satisfy the permissible limits or it is not possible to obtain chemical analysis data readily, the suitability of water is tested by making concrete cubes. Concrete of desired grade is prepared with available water with designed proportions and cubes casted for testing.
3. Prepare the same concrete mix with distilled water and cast the cubes in exactly the similar manner as with water of unknown nature.
4. Cure both the sample in respective water under exactly the same conditions.
5. Test both the cube specimens after 7 and 28 days in exactly the same manner. Compare the test results of strength and conditions of the surface of cubes in respect of mix prepared with available water and distilled water.
6. Available water shall be considered suitable if the strengths are not much less and no deterioration observed in case of concrete prepared with available water of unknown quality.

Precautions

1. For assessing the suitability of water for mixing and curing the concrete cube specimen should be prepared and tested under similar set of conditions with the available water of unknown quality to be assessed and distilled water.
2. Mix proportions should be kept exactly the same in both cases.
3. All appliances should be clean.
4. Cement, sand, and coarse aggregate should be the same as likely to be used at site.

Conclusion

Calculate the ratio of average compressive strength of concrete prepared with unknown water and distilled water.