High value generally associated with High-Performance What is High-Performance? High-Early Strength Concrete High-Strength Concrete High-Durability Concrete Self-Consolidating Concrete Reactive Powder Concrete

1. Engr.ArivusudarNagarajan
n.arivusudar@yahoo.com
Special Concrete - High End
Out put Value for Materials

2. High-Value Concrete
 All concrete is high value!
 Cost of material (small)
 Cost of placement (significant)
 Cost of Replacement (HIGH)

3. High-Value Concrete
 High value generally associated with High-
Performance
 What is High-Performance?
 High-Early Strength Concrete
 High-Strength Concrete
 High-Durability Concrete
 Self-Consolidating Concrete
 Reactive Powder Concrete

4. Characteristics of High-Performance
Concretes
 High early strength
 High strength
 High modulus of elasticity
 High abrasion resistance
 High durability and long life in
severe environments
 Low permeability and
diffusion
 Resistance to chemical attack

5. Characteristics of High-PerformanceConcretes
 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

6. Materials Used in High-Performance Concrete
Material Primary Contribution/Desired Property
Portland cement Cementing material / Durability
Blended cement
Cementing 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

7. Materials Used in High-Performance
Concrete
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
Improve workability/reduce paste
Polymer/latex modifiers
Optimally graded aggr.
Durability

8. Selected Properties of High-Performance
Concrete
2% to 5%
Property Test Method Criteria that may be specified
High Strength ASTM C 39 70-140 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
Low Absorption ASTM C 642
High Mod.of Elast. ASTM C 469 More than 40 GPa

9. High-Early-Strength Concrete
 High-early compressive strength ASTMC 39
(AASHTO T 22 ) 20 to 28 Mpa at 3 to 12 hours or 1 to 3
days
 High-early flexural strength ASTMC 7 8
(AASHTO T 9 7 )
2 to 4 Mpa at 3 to 12 hours or 1 to 3 days

10. High-Early-Strength Concrete
 Type III or HE high-early-strength cement
 High cement content 400 to 600 kg/m3
 Low water-cementing materials ratio (0.20 to 0.45 by mass)
 Higher freshly mixed concrete temperature
 Higher curing temperature
May be achieved by —

11. High-Early-Strength Concrete
 Chemical admixtures
 Silica fume (or other SCM)
 Steam or autoclave curing
 Insulation to retain heat of hydration
 Special rapid hardening cements
May be achieved by —

12. High-Strength Concrete
90% of ready-mix concrete
20 MPa - 40 Mpa @ 28-d
(most 30 MPa – 35 MPa)
High-strength concrete
by definition — 28 day –
Compr. Strength ≥ 70 MPa

13. High-Strength Concrete Materials
 9.5 - 12.5 mm nominal maximum size gives
optimum strength
 Combining single sizes for required grading allows
for closer control and reduced variability in
concrete
 For 70 MPa and greater, the FM of the sand should
be 2.8 – 3.2. (lower may give lower strengths and
sticky mixes)
Aggregates —

14. High-Strength Concrete Materials
 Fly ash, silica fume, or slag often mandatory
 Dosage rate 5% to 20% or higher by mass of
cementing material.
Supplementary Cementing Materials —

15. High-Strength Concrete Materials
 Use of water reducers, retarders, HRWRs, or super
plasticizers — mandatory in high-strength concrete
 Air-entraining admixtures not necessary or desirable in
protected high-strength concrete.
 Air is mandatory, where durability in a freeze-thaw environment
is required (i.e.. bridges, piers, parking structures)
 Recent studies:
 w/cm ≥ 0.30—air required
 w/cm < 0.25—no air needed
Admixtures —

16. High-Strength Concrete
 Delays in delivery and placing
must be eliminated
 Consolidation very important to achieve strength
 Slump generally 180 to 220 mm.
 Little if any bleeding—fog or evaporation retarders have to
be applied immediately after strike off to minimize plastic
shrinkage and crusting
 7 days moist curing
Placing, Consolidation, and Curing

17. 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 — High-Durability HPC

18. High-Durability Concrete
 Abrasion Resistance
 Blast Resistance
 Permeability
 Carbonation
 Freeze-Thaw Resistance
 Chemical Attack
 Alkali-Silica Reactivity
 Corrosion rates of rebar
Durability Issues That HPC Can Address

19. High-Durability Concrete
 Cement: 398 kg/m3
 Fly ash: 45 kg/m3
 Silica fume: 32 kg/m3
 w/c: 0.30
 Water Red.: 1.7 L/m3
 HRWR: 15.7 L/m3
 Air: 5-8%
 91d strength: 60 MPa
Case study : Confederation Bridge,Case study : Confederation Bridge,
Northumberland Strait, Prince EdwardNorthumberland Strait, Prince Edward
Island/New Brunswick, 1997Island/New Brunswick, 1997

20. 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

21. Self-Consolidating Concrete

22. SCC for Power Plant in Arun
excello —Mix Proportions
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)
AE admixture as needed for 6% ± 1.5% air content

23. Reactive-Powder Concrete
(RPC)
 Properties:
 High strength — 200 MPa
(can be produced to 810 MPa)
 Very low porosity
 Properties are achieved by:
 Max. particle size ≤ 300 µm
 Optimized particle packing
 Low water content
 Steel fibers
 Heat-treatment

24. Mechanical Properties of RPC
Property Unit 80 MPa RPC
Compressive
strength MPa 80 200
Flexural strength MPa 7 40
Tensile strength MPa 8
Modulus of Elasticity GPa 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

25. Reactive Powder
Concrete

26. What is the typical mix ?
230 kg/m3
710 kg/m3
210 kg/m3
40 - 160 kg/m3
13 kg/m3
140 kg/m3
1020 kg/m3
Cement
Silica fume
Crushed
Quartz
Sand
Fibres
Superplasticizer
Total water
No aggregates !

27. What is the typical mix ?
9 – 10%
28 - 30%
8.5 – 9%
1.7 – 6.5%
0.6%
5.5 – 6%
42 –43%
Cement
Silica fume
Crushed
Quartz
Sand
Fibres
Superplasticizer
Total water
No aggregates !w/c = 0.20

28. n.arivusudar@yahoo.com
Thank You