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Reactive Powder Concrete , as high strength and high performance concrete


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Reactive powder concrete, High strength concrete, high performance concrete, ultra high strength concrete, ultra high performance concrete.

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Reactive Powder Concrete , as high strength and high performance concrete

  2. 2. 1:CONCRETE: • Composite material /artificially built up stone composed of: I. Cement(binding) II. aggregate(inert/strength) III. water (hydration) IV. Admixtures (chemical/minerals) fig: composition of concrete • High compressive strength but weak in tensile.
  3. 3. 2:CLASSIFICATION BASED ON STRENGTH: – Low Strength (<2000psi), 20Mpa – Normal strength (2000-6000psi),20-60 Mpa – High Strength (HPC) (>6000psi), >60 Mpa – Ultra High Strength (UHPC/RPC) ,>200 Mpa • High strength concrete(HSC) Lower w/c ratio (<=0.35) Silica fume is added(to prevent CaOH2 formation) Less workable? BUT super plasticizers are added
  4. 4. Methods of production (HSC) a. High speed slurry mixing -cement water paste + then aggregate added b. Use of cementitious aggregates -high strength aggregate c. Re-vibration -1% porosity reduce = 5% strength gain d. Use of admixtures/to reduce w/c ratio e. Sulphur filling or impregnation/increase strength. f. Preventations of cracks/inhibition.
  5. 5. •High performance concrete(HPC) HIGH : strength/workability/imperm-ability/elasticity/ chemical attack resistance/dimensional stability AND durability. • Ultra high strength/ultra high performance concrete produced by: a. Compaction by pressure b. Helical binding c. Polymerizations d. Reactive powder concrete (RPC)(FURTHER……..)
  6. 6. 3: REACTIVE POWDER CPNCRETE (RPC) • Need of High Strength /durability and ductility concrete. • Eliminated flaws of other types of concrete and use of coarse aggregates. • Consists of very fine powders of Cement, Micro Silica Sand, Quartz Powder, Minimum Water and Steel fibers for ductility. • Ultra high strength range in compression: 200-800 Mpa. • Developed by P Richards and M Cheyrezy Bouygues, construction, in the early 1990s. (Paris) • w/c ratio 0.16-0.24 (sometime 0.13 too)
  7. 7. 3.1: Ingredients of RPC Components parameters function Particle size(μm) Types Sand Good hardness available at low cost Gives strength 150-600 Natural crushed Cement C3S 60%,C2S22% C3A3.8%,C4A47.4% Binding and hydration 1-100 OPC fineness Quartz powder Fineness Maximum reactivity during Heat treating 5-25 microns Crystalline Silica fumes Very low impurities Fills voids, produces secondary hydrates 0.1 – 1 micron Highly Refined 25% weight Steel fibers Good aspect ratio Improves ductility L: 13-25 mm Dia: 0.15 – 0.20 mm Straight 3-10% super plasticizers Less retarding Nature Reduce W/C ratio Polyacrylate
  8. 8. 3.2:RPC MIX and PLACING • Can be mixed and produced in a ready-mix truck and still have similar strengths to those made in a central mixer. • Self-placing, requires no internal vibration. • Despite its composition, the large amount of super plasticizer still makes it workable. Function parameters • Give strength to aggregate • Binding material • Maximum reactivity during heat-treating • Filling the voids • Improve ductility • Reduce water binding
  9. 9. 3.3: PRINCIPLES: Chard and Cheyrezy gave following principles for developing RPC: 1. Elimination of coarse aggregates for enhancement of homogeneity 2. Utilization of the pozzolanic properties of silica fume 3. Optimization of the granular mixture for the enhancement of compacted density 4. The optimal usage of super plasticizer to reduce w/c and improve workability 5. Application of pressure (before and during setting) to improve compaction 6. Post-set heat-treatment for the enhancement of the microstructure 7. Addition of small-sized steel fibers to improve ductility
  10. 10. 3.4: PROPERTIES OF RPC • Compressive strength(>100 Mpa in 24 hours of initial set) • Flexural strength • Water absorption • Water permeability • Resistance to chloride ion penetration • Homogeneity • Compactness • Micro-structure • Material ductility • Almost no shrinkage or creep • Light weight • Long life • Aesthetic possibilities
  11. 11. a. compressive strength • Higher compressive (200-800MPa)
  12. 12. b. Flexural Strength • Plane RPC possess high flexural strength than HPC (Up to 100mpa) • By introducing steel fibers, RPC can achieve high flexural strength. c. Water Absorption -less than 7-10 times of HPC d. Water permeability -28th day water permeability of RPC is negligible. -7 times less than HPC -fiber increase surface water permeability
  13. 13. e..Resistance to chloride ion penetration • Increases when heat curing is done in concrete • Heat cured RPC show higher value than normal cured RPC. • This property of RPC enhances its suitability for use in nuclear waste containment structures. f. Homogeneity • Improved by eliminating all coarse aggregates • Dry components for use in RPC is less than 600 micro meter. g. Compactness: • Application of pressure before and during concrete setting period. h. Microstructure: • Microstructure of the cement hydrate can be changed by applying heat treatment during curing. i. material ductility: • Material ductility can be improved through the addition of short steel fibers.
  14. 14. 3.5: RPC APPLICATIONS Light weight ,high span bridges, multi story buildings, high strength and in seismic region, inside water structures etc. Real structures: First bridge in Sherbrook, Quebec, Canada. (230MPa)
  15. 15. • Portugal has used it for seawall anchors. • Australia has used it in a vehicular bridge. • France has used it in building power plants. • Qinghai-Tibet Railway Bridge. • Shawnee's Light Rail Transit Station. Basically, structures needing - light and thin components, -things like roofs for stadiums, -long bridge spans, extra safety or security such as blast resistant structures.
  16. 16. Qinghai-Tibet Railway Bridge
  17. 17. 3.6:BENEFITS: • It has the potential to structurally compete with steel. • Superior strength combined with higher shear capacity result in significant dead load reduction. • RPC can be used to resist all but direct primary tensile stress. Tensile strength up to 50 MPa • Improved seismic performance by reducing inertia load with lighter member. • Low &non-interconnected porosity diminishes mass transfer, making penetration of liquid/gas non- existent.
  18. 18. Fig: showing bending stress
  19. 19. 3.7:LIMITATIONS: • RPC mixture design, the components are more expensive elements. • No code ( no any formal worldwide documents but is under research ) • The fine sand used in RPC becomes equivalent to the coarse aggregate of conventional concrete, the Portland cement plays the role of the fine aggregate and the silica fume(lack) that of the cement. • The mineral component causes cost (5 to 10 times higher than HPC).
  20. 20. 3.7:CONCLUSIONS: • Owing to its high durability, RPC can even replace steel in compression members where durability issues are at stake (e.g. in marine condition). • Since RPC is in its developing stage, the long-term properties are not known. • It would be under research what if using other ashes rather than silica fume e.g. Pulverized fly ash etc.
  21. 21. Bibliography: 1. Concrete technology B.L Gupta & Amit Gupta 2. Concrete technology M.S.Shetty . 3. Objective guides for civil engineers D. Prasad 4. Properties of Concrete, A.M. Neville 5. 6. 7. 41611973 8. concrete2-57310486
  22. 22. • Examples: Qinghai-Tibet Railway Shawnessy Light Rail Transit Station in Iowa (2004) First UHPC Bridge in U.S.  Sherbrooke pedestrian bridge, in Canada.