7 curing concrete

Curing Concrete

ByProf. Adel El Kordi

&Dr. Meheddene Machaka

Structural EngineeringDepartment

Faculty of EngineeringBeirut Arab University

CVLE 321

Curing

Moisture Temperature Time

Curing requires adequate —

If any of these factors areneglected, the desiredproperties will not develop

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Increased Strength Water tightness Abrasion resistance Freeze-thaw resistance Volume stability

Effect of Adequate Curing onHardened Concrete

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Effect of Moist Curing

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Effect of Curing Temperature on Strength

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Effect of Curing Temperature on Strength

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Curing Methods andMaterials

1. Supply additional water with: Ponding or immersion

Spraying or fogging

Saturated wet coverings

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Curing of Concrete by SupplyingWater (immersion)

Evaporation fromwater surface

Concrete

Water suppliedfrom externalsource

Saturated

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Curing Methods

2. Seal in mixing water:

Plastic sheets

Membrane-formingcuring compounds

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Membrane-forming Curing compounds

Reduced evaporationfrom water surface

Concrete

Curingmembrane

Saturated

Partially saturated

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Curing compounds should be able to maintain the relativehumidity of the concrete surface above 80% for seven daysto sustain cement hydration.

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Steam CuringSteam curing is advantageous where:1- Early strength gain in concrete.2- Additional heat of hydration is required, as in cold weather.

Two methods of steam curing are used:1- live steam curing at atmospheric pressure2- high-pressure steam curing in autoclaves.

A typical live steam-curing cycle consists of:(1)Initial delay prior to steaming.(2)Increasing the temperature.(3)Holding the maximum temperature constant.(4)Decreasing the temperature

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1- live steam curing at atmospheric pressure

Strength vs. Steam Curing

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Strength vs. Curing Temperature

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One-day strength increases with increasing curing temperature, but 28-day strength decreases with increasing curing temperature .

The relationship between curing temperature and compressivestrength for 1 day and 28 days curing time.

Sealing Compounds

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