high-performance concrete finale

7/31/2019 High-performance Concrete Finale

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HIGH-PERFORMANCE CONCRETE


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Topics


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Introductions Latest demands regarding reinforced concrete

structures, with ever expansion in height and length,require the use of concrete with superior physical andmechanical properties. The use of high performance

concrete for reinforced concrete structures meets therequirements, with several advantages in terms ofcost and slenderness. The durability of high strengthconcrete is also extremely beneficial in a long term

analysis.


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Definitions ACI (American Concrete Institute)defined high-

performance concrete as a concrete meeting specialcombinations of performance and uniformityrequirements that cannot always be achieved routinely

using conventional constituents and normal mixing,placing, and curing practice.


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Burj Khalifa BuildingNew Benicia-Martinez Bridge

High-performance concrete


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High-performance concretecharacteristics High strength High early strength

High modulus of elasticity

High abrasion resistance

High durability and long life in severe environments

Low permeability and diffusion

Resistance to chemical attack

High resistance to frost and deicer scaling damage

Toughness and impact resistance

Volume stability Ease of placement

Compaction without segregation Inhibition of bacterial and mold growth


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Characteristics that may be

considered critical for

particular application Ease of placement

Compaction without segregation

Early age strength &Long-term strength andmechanical properties

Permeability

Heat of hydration Long life in severe environments Note: according to the ACI definition, durability under severe environmental conditions is an

optional, not a mandatory requirement for HPC.


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Material Used in HPCMaterial Primary

contribution/Desiredproperty

Portland cement Cementing material/durability

Blended cement Cementingmaterial/durability/highstrength

Fly ash or Silica fume Cementingmaterial/durability/highstrength

Admixture Ari Entraining

Chemical AdmixtureMineral Admixture

Optimally graded aggregate Work ability /Reduce pastedemand

Polymer/latex modifiers Durability


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HSC compare to Normal ConcreteFlowability/Pumpability EasierWorkability/Compactability EasierBleeding None or NegligibleFinishing QuickerSetting Time Slower up to 2 hEarly Strength (up to 7-day) Lower but can be acceleratedUltimate Strength- 90day +

Higher

Crack Resistance Plastic Shrinkage Thermal Shrinkage Lower Drying Shrinkage

HigherHigher (If unprotected)LowerLower


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HSC compare to Normal Concrete(continue)Resistance to Penetration of Chloride Ions Very high after 3 monthsElectrical Resistivity Very high after 3 monthsDurability Resistance to Sulfate Attack

Resistance to Alkali-Silica Expansion Resistance to Reinforcement Corrosion

Very high

Very highHigh

Cost Materials Labor Life Cycle

LowerSimilarVery low

Environmental Benefits ( Reduced CO2 emission) Very high


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Example of building Off-shore

Oil drilling platform

Long span bridge

Bridge-deck Pavements

Parking Structure


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Conclusion The application of new superplastizicer and powders in

high performance concrete give the opportunity toproduce self-compacting concretes that easily reach acompressive strength of more than 150 MPa. These

concretes show a very good workability in the fresh state,also the hardened concrete shows excellent quality.Future interests will try to reduce autogenous shrinkage tominimize the crack tendency of the young concrete.Further investigations to optimize the mix proportions willaim to the application of this concrete on site.


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Reference

high-performance concrete finale

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