9 high performance concrete

High-Performance Concrete

CVLE 519

Concrete Technology

Dr. Adel El Kordi

Professor

Civil and Environmental Engineering

Department

Faculty of Engineering

Characteristics of High-Performance Concretes

1. High strength

2. High early strength

3. High modulus of elasticity

4. High abrasion resistance

5. High durability and long life in

severe environments

6. Low permeability and diffusion

7. Resistance to chemical attack

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Characteristics of High-Performance Concretes

8. High resistance to frost and deicer scaling damage

9. Toughness and impact resistance

10.Volume stability

11.Ease of placement

12.Compaction without segregation

13.Inhibition of bacterial and mold growth

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Materials Used in High-Performance Concrete (1)

Material Primary Contribution/Desired

Property

Portland cement Cementing material / Durability

Blended cementCementing material /

Durability /

High strength

Fly ash / Slag / Silica fume

Calcined clay/ Metakaolin

Calcined shale

Superplasticizers Flowability

High-range water reducers Reduce water-cement ratio

Hydration control admix. Control setting4

Materials Used in High-Performance Concrete (2)

Material Primary contribution/Desired property

Retarders Control setting

Accelerators Accelerate setting

Corrosion inhibitors Control steel corrosion

Water reducers Reduce cement and water content

Shrinkage reducers Reduce shrinkage

ASR inhibitors Control alkali-silica activity

Polymer/latex modifiers Durability

Optimally graded aggr. Improve workability/reduce paste

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Selected Properties of High-Performance Concrete (1)

Property Test Method Criteria that may be specified

High Strength ASTM C 39 40-140 MPa @ 28 to 91 days

High early comp.

strength

ASTM C 39 20-30 MPa @ 3-12 hrs.or 1-3 days

High early Flex.

Strength

ASTM C 78 2-4 MPa @ 3-12 hrs.or 1-3 days

Abrasion Resistance ASTM C 944 0-1 mm depth of wear

Low Permeability ASTM C 1202 500 to 2000 coulombs

Chloride Penetration AASHTO T

259/260

Less than 0.07% Cl at 6 months

High Resistivity ASTM G 59 —

Low Absorption ASTM C 642 2% to 5%6

Selected Properties of High-Performance Concrete (2)

Property Test Method Criteria that may be

spec.

Low diffusion coeff. Wood, Wilson, Leek 1000 x 10-13 m/s

Resistance to

chemical attack

sat. solution in wet/dry

environmentNo deterioration after 1 yr.

Sulphate attack ASTM C 1012 0.1% max. exp. @ 6 mos.

High Modulus of

Elasticity. (E)ASTM C 469 More than 40 GPa

High resistance to

F/T damage

ASTM C 666

Procedure A

Durability Factor 95-100 @

300 -1000 cycles

High resistance to

deicer scalingASTM C 672

Rating 0-1 or mass loss 0 to

0.5 kg/m3 after 50-300

cycles

Low shrinkage ASTM C 157 Less than 400 millionths

Low creep ASTM C 512 Less than normal concrete 7

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Some examples of attributes that may be improved in a

High-performance concrete are:

•Strength

•Ease of placement

•Compaction without segregation

•Early age strength

•Long-term mechanical properties

•Permeability

•Density

•Heat of hydration

•Toughness

•Volume stability

•Long life in severe environments

High-Early-Strength Concrete

High-early compressive strength

ASTM C 39 (AASHTO T 22)

20 to 28 MPa (3000 to 4000 psi)

at 3 to 12 hours or 1 to 3 days.

High-early flexural strength

ASTM C 78 (AASHTO T 97)

2 to 4 MPa (300 to 600 psi)

at 3 to 12 hours or 1 to 3 days.

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1. Type III or HE high-early-strength cement

2. High cement content 400 to 600 kg/m3 .

3. Low water-cementing materials ratio (0.20 to 0.45 by mass)

4. Higher freshly mixed concrete temperature.

5. Higher curing temperature

May be achieved by —

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6. Chemical admixtures

7. Silica fume (or other supplementary

cementing materials)

8. Steam or autoclave curing

9. Insulation to retain heat of hydration

10. Special rapid hardening cements

May be achieved by —

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Cement: 513 kg/m3

w/c: 0.25

Silica fume: 43 kg/m3

Fine aggr.: 685 kg/m3

Coarse aggr.: 1150 kg/m3

HRWR: 15.7 L/m3

28d strength: 119 MPa


Two Union Square Seattle, 1988

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High-Durability Concrete

1970s and 1980s focus on High-

Strength HPC.

Today focus on concretes with high

durability in severe environments

resulting in structures with long life.

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1. Abrasion Resistance

2. Blast Resistance

3. Permeability

4. Carbonation

5. Freeze-Thaw Resistance

6. Chemical Attack

7. Alkali-Silica Reactivity (helps combat)

8. Corrosion rates of rebar (high resistivity)

Durability Issues That HPC Can Address

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Cement: 398 kg/m3

Fly ash: 45 kg/m3

Silica fume: 32 kg/m3

Fine aggr.: 695 kg/m3

Coarse aggr.: 1215 kg/m3

w/c: 0.30

Water Red.: 1.7 L/m3

HRWR: 15.7 L/m3

Air: 5-8%



Confederation Bridge, Northumberland Strait,

Prince Edward Island/New Brunswick, 1997

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Self-Consolidating Concrete

Developed in 1980s — Japan

Increased amount of

Fine material

(i.e. fly ash or limestone filler)

HRWR/Superplasticizers

Strength and durability same as

conventional concrete

Self-consolidating concrete (SCC) also

known as self-compacting concrete —

flows and consolidates on its own

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Self-Consolidating Concrete

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Portland cement (Type I) 297 kg/m3

Slag cement 128 kg/m3

Coarse aggregate 675 kg/m3

Fine aggregate 1,026 kg/m3

Water 170 kg/m3

Superplasticizer ASTM C 494, Type F

(Polycarboxylate-based) 1.3 L/m3

AE admixture as needed for 6% ± 1.5% air content

SCC for Power Plant in Pennsylvania—Mix Proportions

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J-Ring Test for SCC

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Reactive-Powder Concrete (RPC)

Properties:

High strength — 200 MPa (can be produced to 810 MPa)

Very low porosity

Properties are achieved by:

Max. particles size 300 m

Optimized particle packing

Low water content

Steel fibers

Heat-treatment

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Mechanical Properties of RPC

Property Unit 80 MPa RPC

Compressive

strengthMPa (psi) 80 (11,600) 200 (29,000)

Flexural strength MPa (psi) 7 (1000) 40 (5800)

Tensile strength MPa (psi) 8 (1160)

Modulus of Elasticity GPa (psi) 40 (5.8 x 106) 60 (8.7 x 106)

Fracture Toughness 103 J/m2 <1 30

Freeze-thaw RDF 90 100

Carbonation mm 2 0

Abrasion 10-12 m2/s 275 1.2

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Reactive Powder Concrete

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