Water

Water is an important ingredient of concrete. As a general guidance, if the water is fit for drinking, it is fit for making concrete. However, some water containing small traces of sugar is not suitable for concrete. Another yardstick adopted is that if the pH is between 6 and 8 the water is considered to be suitable.

The best method is to use the water from the particular source and sample concrete is prepared for testing. The concrete is tested for 7 days and 28 days compressive strengths; if 90% result is obtained it can be considered to be suitable.

The following guidelines may also be adopted:

1. Neutralizing 100 ml sample of water using phenoplhaline as an indicator should not require more than 5 ml of 0.02 N NaOH.
2. Neutralizing 100 ml of sample of water using a mixed indicator should not require more than 25 ml of 0.02 N H₂SO₄.

BIS (IS: 456–2000) recommends the permissible limits for solids enlisted in Table 8.1.

Table 8.1 Materials and permissible solids

Source: IS: 456–2000.