High density concrete, high strength concrete and high performance concrete.


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High density concrete, high strength concrete and high performance concrete.

  1. 1. High Density Concrete  High Density=Heavyweight  Density should be more than 2600 kg/m3  Dens CRETE  Offers more strength  Can be used everywhere, in all construction practices  Resistant to extreme weather
  2. 2. Main Components:  Cement --- Provides limited strength --- Not that useful in high density concrete --- Used as binding material Water Aggregates Admixtures
  3. 3. Natural Aggregates •Aggregates are obtained from iron ores •Large amount of iron content •Varying densities so variety of high density concrete can be produced Types: 1. 2. 4. 3.
  4. 4. Man-made (Synthetic) Aggregates: Iron Shots Chilcon Synthetic Aggregates Fergran Lead Shots
  5. 5. Admixture:  Water reducing admixture is used  Consists Lignosulfonic acid, carboxylic acids  Use of Water reducing admixture in high density concrete –Increase workability –Reduces water requirement –Reduces cement content requirement –High early strength
  6. 6. Application:  High density radiation shielding  Precast blocks  Mass concrete projects  High density concrete applications columns  Gravity seawall, coastal protection & breakwater structures  Bridge counterweights  Ballast for ocean vessels  Off shore platforms noise and vibration dampening
  7. 7. Advantages:  High neutron and gamma ray attenuation  Good mechanical properties  Relatively low initial and maintenance cost  Easy to construct Disadvantages: Space Weight
  8. 8. Production:
  9. 9. High Strength Concrete:  Using Type I Portland cement, gravel or crushed limestone coarse aggregate, sand from a local deposit, and for some mixes a waterreducing retarding admixture.  Water-cement ratios ranged from 0.70 to 0.32  Concrete strength of 90-120 MPa  Uniaxial compressive strengths ranged from about 21 to 76 MPa.  Pertaining to compressive strength, strength gain with age, specimen size effect, effects of drying, stress-strain curves, static modulus of elasticity, Poisson’s ratio, modulus of ruptuie, and split cylinder strength.  Has to take care about mix proportioning, shape of aggregates, use of supplementary cementitious materials, silica fume and super plasticizers.
  10. 10. Special methods of making high strength concrete  Seeding: This involves adding a small percentage of finely ground, fully hydrated Portland cement to the fresh concrete mix. This method may not hold much promise.  Revibration: Controlled revibration removes all the defects like bleeding, water accumulates , plastic shrinkage, continuous capillary channels and increases the strength of concrete.  High speed slurry mixing: This process involves the advance preparation of cement - water mixture which is then blended with aggregate to produce concrete.  Use of admixtures: Use of water reducing agents are known to produce increased compressive strength.
  11. 11.  Inhibition of cracks: If the propagation of cracks is inhibited, the strength will be higher. Concrete cubes made this way have yielded strength up to 105MPa.  Sulphur Impregnation: Satisfactory high strength concrete have been produced by impregnating low strength porous concrete by sulphur. The sulphur infiltrated concrete has given strength up to 58MPa.  Use of Cementitious aggregates: Cement fondu is kind of clinker. Using Alag as aggregate, strength up to 25MPa has been obtained with water cement ratio 0.32.
  12. 12. Fire resistance of High Strength Concrete:
  13. 13. Strength-weight ratio becomes comparable to steel: Strength-Weight Ratio 45 40 35 30 25 20 15 10 5 0 Structural steel Concrete High strength concrete Lightweight HSC
  14. 14. High-strength concrete is often used in bridges
  15. 15. HIGH PERFOMANCE CONCRETE: “A high performance concrete is a concrete in which certain characteristics are developed for a particular application and environments”:            Ease of placement Compaction without segregation Early-age strength Long term mechanical properties Permeability Durability Heat of hydration Toughness Volume stability Long life in severe environments High resistance to frost and deicer scaling damage  Toughness and impact resistance  Volume stability
  16. 16. High-performance concrete is often used in bridges and tall buildings
  17. 17. 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 Cementing material/durability/high strength Slag Cementing material/durability/high strength Silica fume Cementing material/durability/high strength Calcined clay Cementing material/durability/high strength Metakaolin Cementing material/durability/high strength Calcined shale Cementing material/durability/high strength
  18. 18. Super plasticizers Flow ability High-range water reducers Reduce water to cement ratio Hydration control admixtures Control setting 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 reactivity Polymer/latex modifiers Durability Optimally graded aggregate Improve workability and reduce paste
  19. 19. The required durability characteristics are governed by the application of concrete and by conditions expected to be encountered at the time of placement. These characteristics should be listed. Environment Environment Concrete Impact Resistance Durable Concrete (HPC) Deterioration Concrete
  20. 20. REFERANCE: Publication:Journal Proceedings Author(s):Ramon L. Carrasquilio, Arthur H. Nilson, and Floyd 0. Slate CSTR49: „Design guidance for high strength concrete‟, Concrete Society Technical Report No. 49, The Concrete Society, 1998 CEB-FIP Model code for concrete structures, 1990. Comité Euro-International du Beton. Thomas Telford, London, 1993. Bulletin d‟Information No. 213/214. 437 pp. BRITISH STANDARDS INSTITUTION. BS 8110 Structural use of concrete Part 3: 1985. Design charts for singly reinforced beams, doubly reinforced beams and rectangular columns. 112 pp. BS EN 1992-1-1:2004 Eurocode 2. Design of concrete structures. General rules and rules for buildings Aı tcin, P.-C., High-Performance Concrete, Modern Concrete Technology 5, E & FN Spon, London, 1998 ASCE, High-Performance Construction Materials and Systems, Technical Report 935011, American Society of Civil Engineers, New York, April 1993. Farny, James A., and Panarese, William C., High-Strength Concrete,EB114, Portland Cement Association, 1994 Perry, V., “Industrialization of Ultra-High Performance Ductile Concrete,” Symposium on High-Strength/High-Performance Concrete, University of Calgary, Alberta, November 1998.