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Quality of Water. Materials of Construction Dr. TALEB M. AL-ROUSAN. Quality of water. Very important Impurities in water may: interfere with the setting of cement. Adversely affect strength of concrete. Cause staining of concrete surface. Lead to corrosion of reinforcement.

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Quality of water

Quality of Water

Materials of Construction


Quality of water1
Quality of water

  • Very important

  • Impurities in water may:

    • interfere with the setting of cement.

    • Adversely affect strength of concrete.

    • Cause staining of concrete surface.

    • Lead to corrosion of reinforcement.

    • Cause efflorescence.

    • Reduce durability.

    • Volume instability.

Mixing water
Mixing Water

  • Water should be fit for drinking.

  • Limits may be set on chlorides, sulfates, alkalies, and dissolved solids.

  • Dissolved solids < 2000 ppm

  • If drinking water has high concentration of Sodium or Potassium it will be unsuitable to be used for mixing because of danger of Alkali-Aggregate reaction.

  • Alkali Carbonate & bicarbonate (Na, K) affect setting times of different cement (accelerate or retard), and if available in higher contents may cause strength reduction.

  • Sulfates: High sulfate content may cause expansive reactions and deterioration.

Mixing water cont
Mixing Water Cont.

  • Oils: Mineral oils (Petroleum) has less effect than animal or vegetable oils. Oils > 2.5% by mass of cement tends to reduce strength.

  • Water carrying sanitary sewage: Treated water that has up to 20 ppm solids is OK to be used.

  • Acid water : depends on pH (< 3 cause handling problems).

  • Water used to wash out truck mixers can be used because solids in it are concrete ingredients.

  • Wash water & industrial water: can be used but high solid content will reduce strength.

Mixing water cont1
Mixing Water Cont.

  • Sugar:

    • Small amounts of sucrose (0.03 – 0.15% by mass of cement) retard setting of cement, and may improve 28 days strength and reduce the 7 days strength.

    • Sugar > 0.25% of cement may cause rapid setting and reduce 28 days strength.

  • Water not fit for drinking can be used.

  • Rule: Any water of (pH = 6.0 – 8.0 which doesn’t taste saline or brackish) is suitable for use.

Mixing water cont2
Mixing Water Cont.

  • Sea water can be used but generally inadvisable.

    • Leads to higher early strength but a lower long-term strength (15% loss).

    • Sea water or any water with high chlorides content tend to cause efflorescence and persistent dampness. Should not be used where appearance of concrete is of importance.

    • Sea water increase the risk of corrosion of reinforcement.

    • When reinforced concrete is permanently in water (sea or fresh) the use of sea water seems to have no ill-effects.

Curing water
Curing Water

  • Generally, water satisfactory for mixing is also suitable for curing purposes.

  • Iron or organic matter may cause staining.

  • Curing water should be free from substances that attack hardened concrete such as: water containing free CO2 (water formed by melting ice or condensation), which dissolves Ca(OH)2 and causes surface erosion.

Tests on water
Tests on Water

  • To determine water suitability for mixing compare setting time of cement and strength of mortar cubes using water in question with results obtained using known good water.

  • 10% variation is tolerated for strength.

  • Such tests are also recommended when water contains dissolved solids in excess of 2000 ppm or alkali carbonate or bicarbonate in excess of 1000 ppm.

  • For curing water, performance tests involving simulated wetting and evaporation can be done to check for staining which can not be done using chemical analysis.