High-Performance Concrete

ByDr. Adel El Kordi

ProfessorStructural Engineering

Department Faculty of EngineeringAlexandria University

CIVE 570Spring 2012

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

Characteristics of High-Performance Concretes

8. High resistance to frost and deicer scaling damage

9. Toughness and impact resistance

10.Volume stability11.Ease of placement12.Compaction without

segregation13.Inhibition of bacterial and

mold growth

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 setting

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

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

H-E Comp. Strength ASTM C 39 20-30 MPa @ 3-12 hrs.or 1-3 days

H-E 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%

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 environment No deterioration after 1 yr.

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

High Mod.of Elast. (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 todeicer scaling

ASTM C 672Rating 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

High-Early-Strength Concrete

n 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. n 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.

High-Early-Strength Concrete

1. Type III or HE high-early-strength cement2. 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 temperature5. Higher curing temperature

May be achieved by —

High-Early-Strength Concrete

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 —

n Cement: (865 lb/yd3)

n w/c: 0.25n Silica fume: (72 lb/yd3)n Fine aggr.: (1155 lb/yd3)n HRWR: (420

oz/yd3)n 28d strength: (17,200

psi)n 91d strength: (21,000

psi)

n Cement: 513 kg/m3

n w/c: 0.25n Silica fume: 43 kg/m3

n Fine aggr.: 685 kg/m3

n HRWR: 15.7 L/m3

n 28d strength: 119 MPan 91d strength: 145 MPa

Two Union Square Seattle, 1988

High-Durability Concrete

n 1970s and 1980s focus on High-Strength HPC

n Today focus on concretes with high durability in severe environments resulting in structures with long life

High-Durability Concrete

n Abrasion Resistancen Blast Resistancen Permeabilityn Carbonationn Freeze-Thaw Resistancen Chemical Attackn Alkali-Silica Reactivity

(helps combat)n Corrosion rates of rebar

(high resistivity)

Durability Issues That HPC Can Address

n Cement: 398 kg/m3 (671 lb/yd3)

n Fly ash: 45 kg/m3 (76 lb/yd3)

n Silica fume: 32 kg/m3 (72 lb/yd3)

n w/c: 0.30n Water Red.: 1.7 L/m3 (47

oz/yd3)n HRWR: 15.7 L/m3 (83

oz/yd3)n Air: 5-8%n 91d strength: 60 MPa (8700

psi)

High-Durability ConcreteConfederation Bridge, Northumberland Strait, Prince Edward Island/New Brunswick, 1997

Self-Consolidating Concrete

n Developed in 1980s — Japann Increased amount of

u Fine material (i.e. fly ash or limestone filler)

u HRWR/Superplasticizersn Strength and durability same as

conventional concrete

Self-consolidating concrete (SCC) also known as self-compacting concrete —flows and consolidates on its own

Self-Consolidating Concrete

Portland cement (Type I) 297 kg/m3 (500 lb/yd3)

Slag cement 128 kg/m3 (215 lb/yd3)

Coarse aggregate 675 kg/m3 (1,137 lb/yd3)

Fine aggregate 1,026 kg/m3 (1,729 lb/yd3)

Water 170 kg/m3 (286 lb/yd3)

Superplasticizer ASTM C 494, Type F (Polycarboxylate-based) 1.3 L/m3 (35 oz/yd3)

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

SCC for Power Plant in Pennsylvania—Mix Proportions

J-Ring Test for SCC

Reactive-Powder Concrete (RPC)

n Properties:u High strength — 200 MPa

(can be produced to 810 MPa) u Very low porosity

n Properties are achieved by:u Max. particles size 300 mu Optimized particle packingu Low water contentu Steel fibersu Heat-treatment

Mechanical Properties of RPC

Property Unit 80 MPa RPCCompressive strength MPa (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

Reactive Powder Concrete