6.1. Requirements of Water for Construction

Water used in construction should be clean and free from deleterious materials such as oil, acid, alkali, salts, sugar, organic materials, or other substances that may be harmful to concrete or steel.

For any construction project, water is a crucial component that facilitates various processes, especially in concrete preparation. The quality of water is paramount; it should be devoid of harmful substances. This means that it should not contain oils, acids, alkalis, or sugars, as these can damage the integrity of concrete and steel. The emphasis on purity is because impurities can lead to weakness in the construction materials.

Think of constructing a building like baking a cake. Just as using old or spoiled ingredients can ruin the cake, using contaminated water can compromise the strength and durability of the structure.

Water used for mixing concrete should:

• Facilitate proper hydration of cement.
• Ensure sufficient workability without segregation.
• Not contain substances that adversely affect setting time or strength. Specifications:
• pH should generally be between 6 to 8.
• Total dissolved solids (TDS) should be less than 2000 mg/L.
• Organic content should not exceed 200 mg/L.
• Chloride content should be less than 500 mg/L for RCC and less than 1000 mg/L for plain concrete.
• Sulphate content should be less than 400 mg/L.

When mixing concrete, the water used plays several important roles. It not only helps the cement hydrate (which is essential for the strength of concrete) but also ensures the right consistency so that the mix is workable and doesn’t separate. To ensure the water's suitability, specific measurements are recommended. The pH level should be neutral to slightly alkaline (between 6 to 8). The total dissolved solids should be low, as high levels can interfere with the chemical processes needed for setting and hardening. Organic and chloride contents are also closely monitored to ensure they don't exceed specified limits.

Imagine trying to mix pudding with too much salt or sugar added; it would ruin the texture and taste. Similarly, using water with undesirable elements can ruin the concrete mixture.

Curing water is used to maintain moisture in concrete for hydration. Requirements:

• Should not contain large amounts of salts or acids that can react with concrete.
• Clean and free from contaminants.
• Especially important when using recycled or groundwater sources.

After concrete is poured, it needs to stay moist for an extended period to continue the hydration process, which is essential for gaining strength. The water used during the curing process must be clean, without high levels of salts or acids, so that it doesn't react negatively with the concrete, which could lead to damage. This is particularly important if the water is sourced from recycled sources or groundwater, as these can often contain various impurities.

Think of watering a plant; if you use clean water, the plant thrives, but if you water it with heavily salted water, it could wither or die. Similarly, for concrete to gain strength, it needs pure, untainted water during curing.

Water must not leave deposits on equipment. Must be free from oils and suspended particles that can affect reuse or pollute surrounding materials.

Clean water is necessary for maintaining construction equipment, as dirty water can leave residues and deposits that could hinder the performance of the machinery or contaminate materials in subsequent uses. This cleanliness ensures that machinery functions efficiently and that the materials used in construction maintain their quality.

Just like washing your car with dirty water leads to streaks and spots, using contaminated water to clean construction tools can affect their performance and the materials they come into contact with.

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