High-Performance Concrete

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2 Characteristics of High- Performance s 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

3 Characteristics of High- Performance s 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

4 Materials Used in High- Performance (1) Material Portland cement Blended cement Fly ash / Slag / Silica fume Calcined clay/ Metakaolin Calcined shale Superplasticizers High-range water reducers Hydration control admix. Primary Contribution/Desired Property Cementing material / Durability Cementing material / Durability / High strength Flowability Reduce water-cement ratio Control setting

5 Materials Used in High- Performance (2) Material Retarders Accelerators Corrosion inhibitors Water reducers Shrinkage reducers ASR inhibitors Polymer/latex modifiers Optimally graded aggr. Primary contribution/desired property Control setting Accelerate setting Control steel corrosion Reduce cement and water content Reduce shrinkage Control alkali-silica activity Durability Improve workability/reduce paste

6 Selected Properties of High- Performance (1) Property High Strength H-E Comp. Strength H-E Flex. Strength Abrasion Resistance Low Permeability Chloride Penetration High Resistivity Low Absorption Test Method ASTM C 39 ASTM C 39 ASTM C 78 ASTM C 944 ASTM C 1202 AASHTO T 259/260 ASTM G 59 ASTM C 642 Criteria that may be specified to 91 days hrs.or 1-3 days hrs.or 1-3 days 0-1 mm depth of wear 500 to 2000 coulombs Less than 0.07% Cl at 6 months 2% to 5%

7 Selected Properties of High- Performance (2) Property Low diffusion coeff. Resistance to chemical attack Sulphate attack High Mod.of Elast. (E) High resistance to F/T damage High resistance to deicer scaling Low shrinkage Low creep Test Method Wood, Wilson, Leek sat. solution in wet/dry environment ASTM C 1012 ASTM C 469 ASTM C 666 Procedure A ASTM C 672 ASTM C 157 ASTM C 512 Criteria that may be spec x m/s No deterioration after 1 yr. 0.1% max. 6 mos. More than 40 GPa Durability Factor cycles Rating 0-1 or mass loss 0 to 0.5 kg/m 3 after cycles Less than 400 millionths Less than normal concrete

8 High-Early-Strength 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

9 High-Early-Strength May be achieved by Type III or HE high-early-strength cement High cement content 400 to 600 kg/m 3 (675 to 1000 lb/yd 3 ) Low water-cementing materials ratio (0.20 to 0.45 by mass) Higher freshly mixed concrete temperature Higher curing temperature

10 High-Early-Strength May be achieved by Chemical admixtures Silica fume (or other supplementary cementing materials) Steam or autoclave curing Insulation to retain heat of hydration Special rapid hardening cements

11 Strength Data for Fast-Track Bonded Overlay Age Compressive strength, MPa (psi) Flexural strength, MPa (psi) Bond strength, MPa (psi) 4 hours 1.7 (252) 0.9 (126) 0.9 (120) 6 hours 7.0 (1020) 2.0 (287) 1.1 (160) 8 hours 13.0 (1883) 2.7 (393) 1.4 (200) 12 hours 17.6 (2546) 3.4 (494) 1.6 (225) 24 hours 23.9 (3467) 4.2 (604) 2.1 (302) 7 days 34.2 (4960) 5.0 (722) 2.1 (309) 28 days 40.7 (5900) 5.7 (830) 2.5 (359)

12 Strength Development of HE Strength Cement = 390 kg/m 3 (697 lb/yd 3 ) w/c = 0.46

13 Strength Development of HE Strength Cement = 504 to 528 kg/m 3 (850 to 890 lb/yd 3 ) w/c = 0.46

14 Effect of Blanket Insulation

15 High-Strength 90% of R/M concrete 20 MPa d (most 30 MPa 35 MPa) High-strength concrete by definition 28 day compr. strength 70 MPa (10,000 psi)

16 High-Strength Materials Cements Base selection on: mortar-cube tests comparative concrete strengths at 28, 56, 91 days Use cement yielding highest concrete strength at extended ages (91-days) Cement should have min. 7-day mortar cube strength of 30 MPa (4350 psi) Trial mixture with cement contents between 400 and 550 kg/m 3 (675 and 930 lb/yd 3 )

17 High-Strength Materials Aggregates mm (3/8-1/2 in.) 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 (Lower may give lower strengths and sticky mixes)

18 High-Strength Materials Supplementary Cementing Materials Fly ash, silica fume, or slag often mandatory Dosage rate 5% to 20% or higher by mass of cementing material. Some specs. silica fume 10% max.

19 High-Strength Materials Admixtures Use of water reducers, retarders, HRWRs, or superplasticizers 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 ie. bridges, piers, parking structures Recent studies: w/cm 0.30 air required w/cm < 0.25 no air needed

20 High-Strength Mixing Central Plant or Truck Mixers Truck mixing reduce loads to 90% of rated capacity Prequalification of concrete suppliers is recommended Field trials with full loads delivered to the site or a mock-up are essential to assess the batching, mixing, transporting and placing systems to be used

21 High-Strength Placing, Consolidation, and Curing Delays in delivery and placing must be eliminated Consolidation very important to achieve strength Slump generally 180 to 220 mm (7 to 9 in.) 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

22 Mix Proportions and Properties of High-Strength C + SF + FA C + SF Cement, Type I, kg/m Silica fume, kg/m Fly ash, kg/m 3 59 HRWR Type F, liters/m Retarder, Type D, liters/m Water to cementing materials ratio Slump, mm Compressive strength, 28d, MPa Compressive strength, 91d, MPa Modulus of elasticity, 91d, GPa Drying shrinkage, 369d, millionths

23 Mix Proportions and Properties of High-Strength C + SF + FA C + SF Cement, Type I, lb/yd Silica fume, lb/yd Fly ash, lb/yd HRWR Type F, fl oz/yd Retarder, Type D, fl oz/yd Water to cementing materials ratio Slump, in Compressive strength, 28d, psi 13,300 17,000 Compressive strength, 91d, psi 15,170 18,030 Modulus of elasticity, 91d, million psi Drying shrinkage, 369d, millionths

24 Two Union Square Seattle, 1988 Cement: 513 kg/m 3 (865 lb/yd 3 ) w/c: Silica fume: 43 kg/m 3 (72 lb/yd 3 ) Fine aggr.: 685 kg/m 3 (1155 lb/yd 3 ) HRWR: 15.7 L/m 3 (420 oz/yd 3 ) 28d strength: 119 MPa (17,200 psi) 91d strength: 145 MPa (21,000 psi)

25 High-Durability 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

26 High-Durability Durability Issues That HPC Can Address Abrasion Resistance Blast Resistance Permeability Carbonation Freeze-Thaw Resistance Chemical Attack Alkali-Silica Reactivity (helps combat) Corrosion rates of rebar (high resistivity)

27 High-Durability Confederation Bridge, Northumberland Strait, Prince Edward Island/New Brunswick, 1997 Cement: 398 kg/m 3 (671 lb/yd 3 ) Fly ash: 45 kg/m 3 (76 lb/yd 3 ) Silica fume: 32 kg/m 3 (72 lb/yd 3 ) w/c: 0.30 Water Red.: 1.7 L/m 3 (47 oz/yd 3 ) HRWR: 15.7 L/m 3 (83 oz/yd 3 ) Air: 5-8% 91d strength: 60 MPa (8700 psi)

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

29 Self-Consolidating

30 SCC for Power Plant in Pennsylvania Mix Proportions Portland cement (Type I) 297 kg/m 3 (500 lb/yd 3 ) Slag cement 128 kg/m 3 (215 lb/yd 3 ) Coarse aggregate 675 kg/m 3 (1,137 lb/yd 3 ) Fine aggregate 1,026 kg/m 3 (1,729 lb/yd 3 ) Water 170 kg/m 3 (286 lb/yd 3 ) Superplasticizer ASTM C 494, Type F (Polycarboxylate-based) 1.3 L/m 3 (35 oz/yd 3 ) AE admixture as needed for 6% ± 1.5% air content

31 J-Ring Test for SCC

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

33 Mechanical Properties of RPC Property Unit 80 MPa RPC Compressive 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 10 6 ) 60 (8.7 x 10 6 ) Fracture Toughness 103 J/m 2 <1 30 Freeze-thaw RDF Carbonation mm 2 0 Abrasion m 2 /s

34 Reactive Powder