4.3.2 Workability of Fresh Concrete Definition Workability Importance of Workability MobilityViscidity Water retention

Fresh ConcreteFresh Concrete –Fresh Concrete is the concrete before hardened, e.g., concrete composite. WorkabilityWorkability –The properties of Fresh Concrete have sufficient workability to be mixed, transported, and placed properly. Definition Workability of Fresh Concrete

Concrete in Construction Fig Concrete in Construction

Concrete which cannot be placed properly will not produce qualified structures regardless of the qua1ity of the mixture.Concrete which cannot be placed properly will not produce qualified structures regardless of the qua1ity of the mixture. Concrete which may be considered suitable for one structure may not for another.Concrete which may be considered suitable for one structure may not for another. Workability Importance

Mobility Viscidity WorkabilityWorkability Water retention

Workability Mobility The capacity for a concrete mixture to respond to vibration readily and fill all parts and corners of a form is defined as mobility.The capacity for a concrete mixture to respond to vibration readily and fill all parts and corners of a form is defined as mobility. Overcome interior friction, paste viscidity and fiction between aggregates in composite.Overcome interior friction, paste viscidity and fiction between aggregates in composite.

Workability Viscidity (Plasticity) Viscidity is the property of a concrete mixture which allows it to be molded without segregation.Viscidity is the property of a concrete mixture which allows it to be molded without segregation. SegregationSegregation –Composition of concrete mixture segregates by differences of their density and grain size.

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Workability Water retention The capacity to prevent water bleeding from concrete composite.The capacity to prevent water bleeding from concrete composite. –Bleeding Water flows from composite and raises to the surface of concrete.

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Bleeding Path or Water Package Water Package Floating Paste Settlement Deteriorate durability Cause crazing in Concrete Wreck the bond to new Concrete new Concrete