BITUMEN MIXES FOR ROAD

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BITUMEN MIXES FOR ROAD

  1. 1. A Presentation on “BITUMEN MIXES FOR ROAD” Submitted By: Nikhil Awana 10EAYCE073 Submitted To:- Dr. Sheetal Agrawal HOD Civil Department
  2. 2. INTRODUCTION As per Das et al.(2004); During 1900’s, the bituminous paving technique was first used on rural roads The term ‘foamed asphalt’ refers to a mixture of pavement construction aggregates and foamed bitumen. The foamed bitumen, or expanded bitumen, is produced by a process in which water is injected into the hot bitumen, resulting in spontaneous foaming. The bituminous mix design aims to determine the proportion of bitumen, filler, fine aggregates, and coarse aggregates to produce a mix which is workable, strong, durable and economical. Asphaltic/Bituminous concrete consists of a mixture of aggregates continuously graded from maximum size , typically less than 25 mm, through the fine filler that is smaller than 0.075 mm. Sufficient bitumen is added to the mix so that the compacted mix is effectively impervious and will have acceptable dissipative and elastic properties.
  3. 3.  Sufficient bitumen to ensure a durable pavement.  Sufficient strength to resist shear deformation under traffic at higher temperature.  Sufficient air voids in the compacted bitumen to allow for additional compaction by traffic.  Sufficient workability to permit easy placement without segregation.  Sufficient resistance to avoid premature cracking due to repeated bending by traffic.  Sufficient resistance at low temperature to prevent shrinkage cracks. OBJECTIVES OF BITUMINOUS MIX DESIGN
  4. 4. Requirements of Bituminous mixes  Stability  Durability  Flexibility  Skid resistance  Workability  Desirable properties
  5. 5.  Coarse aggregate (retained on 2.36mm sieve)  Fine aggregate (passing 2.36mm sieve but retained on 75m)  Filler (passing 75m), may be cement.  Binder: Bitumen etc. CONSTITUENTS OF BITUMEN MIX
  6. 6. DEFINITIONS  Binder: A material used to hold solid particles together, i.e. bitumen or tar.  Bitumen: A heavy fraction from oil distillation (also occurs as part of natural asphalt).  Tar: A viscous liquid obtained from distillation of coal or wood.Rarely used in construction currently in the UK.  Asphalt: A mixture of bitumen and mineral filler.Note that Hot Rolled Asphalt is a road surfacing material.  Mastic: An adhering asphalt which is placed with trowelling.  Macadam: A road construction material with binder and coarse aggregate. Tarmacadam was the first road surfacing material.
  7. 7. ROAD CONSTRUCTION TYPES Wearing Course Base Course Roadbase Sub-Base Sub-Base Wearing Course Subgrade(limestone) Lower Base (Crack Resistant) roadbase Subgrade(limeston e)
  8. 8. BITUMINOUS CONSTRUCTION PROCEDURES  Surface Dressing  Grouted Or Penetration Macadam  Built-up Spray Grout  Bitumen Bound Macadam  Bituminous Carpet  Bituminous Concrete
  9. 9. ASPHALT CONCRETE OR (BITUMINIOUS MIXTURE)  Asphalt concrete is a composite material commonly used in construction projects such as road surfaces, airports and parking lots. It consists of asphalt (used as a binder) and mineral aggregate mixed together  Hot mix asphalt concrete (commonly abbreviated as HMAC or HMA) is produced by heating the asphalt binder to decrease its viscosity, and drying the aggregate to remove moisture from it prior to mixing  Warm mix asphalt Concrete (commonly abbreviated as WMA) is produced by adding either zeo-lites waxes, asphalt emulsions, or sometimes even water to the asphalt binder prior to mixing  Cold mix asphalt concrete is produced by emulsifying the asphalt in water with (essentially) soap prior to mixing with the aggregate  Cut-back asphalt concrete is produced by dissolving the binder in kerosene or another lighter fraction of petroleum prior to mixing with the aggregate.
  10. 10. Mastic asphalt concrete or sheet asphalt is produced by heating hard grade blown bitumen (oxidation) in a green cooker (mixer) until it has become a viscous liquid after which the aggregate mix is then added. Natural asphalt concrete can be produced from bituminous rock, found in some parts of the world, where porous sedimentary rock near the surface has been impregnated with upwelling bitumen. HOT MIX ASPHALT HMA is a mixture of coarse and fine aggregates and asphalt binder. HMA, as the name suggests, is mixed, placed and compacted at higher temperature. Dense-Graded Mixes This type of bituminous concrete is a well-graded HMA has good proportion of all constituents are also called Dense bituminous macadam. Dense graded HMA surface Dense graded core sample
  11. 11. Stone Matrix Asphalt (SMA) Stone matrix asphalt (SMA), sometimes called stone mastic asphalt, is a gap-graded HMA originally developed in Europe to maximize rutting resistance and durability in heavy traffic road. SMA Lab Sample SMA Surface Open-Graded Mixes Unlike dense-graded mixes and SMA, an open-graded HMA mixture is designed to be water permeable.Open-graded mixes use only crushed stone (or gravel) and a small percentage of manufactured sands
  12. 12. CHARACTERISTICS OF MATERIAL USED IN BITUMINOUS MIX  Mineral Aggregate Obtained from different natural sources such as glacial deposits or mines.  A highly cubic shape and rough texture to resist rutting and movements.  A hardness which can resist fracturing under heavy traffic loads.  A high resistance to polishing, and  A high resistance to abrasion.  Mineral filler Generally filler plays an important role in properties of bituminous mixture particularly in terms of air voids, voids in mineral aggregate. Different types of mineral fillers are used in the SMA mixes such as stone dust, ordinary Portland cement (OPC), slag cement, fly Ash, hydrated lime etc
  13. 13.  Binder Bitumen acts as a binding agent to the aggregates, fines and stabilizers in bituminous mixtures. Binder provides durability to the mix.  Stabilizing Additives The main stabilizing additives used in mixes can be classified in to different groups;  Fibres’ (Cellulose Fibres, Mineral Fibres, Chemical Fibres)  Polymer  Powder and flour like materials (Silicic acid, Special Filler)  Plastics (Polymer Powders or Pellets)  Natural fiber:-Natural fiber classified into 3 category depending upon the part of plant from where it is extracted  Stem fiber (jute, banana etc.)  Leaf fiber (sisal, pineapple)  Fruit fiber (cotton, coir, oil palm)
  14. 14. Conventional Bituminous Mix Technologies Hot Mix Technologies-Shortfalls  Heating of binder at 150-170 C  Heating of aggregates at 185-200 C  Production at 150-160 C  Laying at 140 C  Compaction at 120 C  Environmental pollution  High energy consumption  Limited work year Solution…!!!  Cold mix technologies using bitumen emulsion as binder
  15. 15. COLD BITUMINOUS MIXES  Cold mix technology eliminates heating of aggregates, bitumen binder, uses cationic bitumen emulsions.  Optimized composition of open graded premix carpet, semi- dense bituminous concrete, microsurfacing and bituminous macadam .  It is environment friendly, offer greater social acceptance, increased paving period, acceptable performance and cost effective.  Technology has found wide acceptance.
  16. 16. PRODUCTION OF COLD MIXES Adding Pre-mix Water Adding Emulsion In Drummixer Cold mix on coneyer belt Discharge of cold to dumper
  17. 17. PREPARATION OF COLD MIX Charging of Aggregates Wetting of Aggregates Emulsion for Cold Mix Discharging of Cold Mix
  18. 18.  Transportation of cold mix  Cold mix shall be discharged in trolleys/wheel barrow  Cold mix shall be transported to site by wheel barrow/tippers  Avoid newly laid surface or tacky road surface while ferrying  Spreading of cold mix  Spread cold mix in half the road-width  Required thickness with spreader  Cold mix turned black from brown  Cold mix aerated for about one hours  Compaction  Compacted with 8-10 ton road roller  Wetting of wheels
  19. 19. Preparation of Marshall Specimens 1100g Blended Aggregates 4 % water content Mix for wetting Addition of emulsion 7,8,9% into aggregates Mixing for uniform coating Cold mix in mould Compaction with 75 Blows on each face Specimens Marshall Specimen Curing for 3 days at 400C Testing for Bulk Density, Stability, flow , Retained Stab. at 250C
  20. 20. TESTING OF COLD MIX
  21. 21. APPLICATIONS OF BITUMEN EMULSIONS Tack coat & priming Crack filling and sealing Repair of pot- holes & depression Surface dressing Premix Carpet Bituminous Macadam Microsurfacing Repair of utility cuts

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