Water Quality Tests for Concrete Construction and Recommended Limits

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There are various tests on water to check its quality for suitability of concrete construction. These tests on water for concrete construction is discussed. Quality of water for construction use is determined in the laboratory. This test is done as per clause 3.1.1 of IS 3025. In civil engineering projects, large quantity of different materials are used and it is necessary to test these materials according to certain set patterns within desirable frequency of testing in order that the quality of final product is maintained.

Water Quality Tests for Concrete Construction

Following are the tests required for quality of water for Concrete construction purpose:

1. pH value test
2. Limits of acidity test
3. Limits of alkalinity test
4. Percentage of solids
   1. Chlorides
   2. Suspended matter
   3. Sulphates
   4. Inorganic solids
   5. Organic solids

Frequency of testing of water

Water from each source shall be got tested before the commencement of work and thereafter once in every three months till the completion of the work. Water from municipal source need to be tested only once in six months. Number of tests for each source shall be three.

Recommended Limits for Concrete Construction Water Tests

Water used for mixing and curing shall be clean and free from injurious quantities of alkalies, acids, oils , salts, sugar, organic materials, vegetable growth or other substance that may be deleterious to bricks, stone, concrete or steel. Potable water is generally considered satisfactory for mixing. The pH value of water shall not be less than the following concentrations represent the maximum permissible values (of deleterious materials in water): a) Limits of acidity: To neutralize 100ml sample of water, using phenolphthalein as an indicator, it should not require more than 5ml of 0.02 normal NaOH. The details of test shall be as given in IS 3025 (Para 22). b) Limits of alkalinity: To neutralize 100ml sample of water, using mixed indicator, it should not require more than 25ml of 0.02 normal H₂SO₄. The details of tests shall be as given in IS 3025 (Para 23). c) Percentage of solids: Maximum permissible limits of solids when tested in accordance with IS 3025 shall be as under:

Types of solids	Limits
Organic solids	200 mg/liter
Inorganic solids	3000 mg/liter
Sulphates	400 mg/liter
Chlorides	2000 mg/liter for concrete not containing embedded steel, and 500 mg/liter for reinforced concrete work
Suspended matter	2000 mg/liter

The physical and chemical properties of ground water shall be tested along with soil investigation and if the water is not found conforming to the requirements of IS 456 – 2000, the tender documents shall clearly specify that the contractor has to arrange good quality water construction indicating the source. (i) Water found satisfactory for mixing is also suitable for curing. However, water used for curing shall not produce any objectionable stain or unsightly deposit on the surface. (ii) Sea water shall not be used for mixing or curing. (iii) Water from each source shall be tested before the commencement of the work and thereafter once in every three months till the completion of the work. In case of ground water, testing shall also be done for different point of drawdown. Water from each source shall be got tested during the dry season before monsoon and again after monsoon. Read More: Effect of Water Impurities on Concrete Strength, Durability and Properties