INTERNATIONAL BITUMEN EMULSION FEDERATION FEDERATION by fla18057

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									I.B.E.F.

INTERNATIONAL BITUMEN EMULSION FEDERATION

FEDERATION INTERNATIONALE DE L'EMULSION DE BITUME
                   Cold mixes

• Definition

    Mixture of aggregates and bitumen emulsion, used
    for:

       minor maintenance and repair works

       wearing courses
                   Cold mixes

• Classification

       according to mix design :
         open-graded                       % voids>15%
         semi-dense graded            15%>% voids >10%
         dense-graded                      10%>% voids

       according to storability :
         storable          fluxed bitumen emulsion base
         for immediate use        pure bitumen emulsion
Open graded cold mixes
                                  mixer
                  Belt conveyor
Aggregates bins
        Open graded cold mixes

• Fields of use
    Minor maintenance works
       pothole patching, leveling, pedestrian areas
       secondary roads

    Small works
       private entrances, sidewalks

    Side works
       trench upper layer
       leveling works around manholes, etc.
Patching and minor works
    Dense Cold Mix Process


manufactured in a mobile cold mix plant

transported on site and laid in a variety of ways
  by hand
  grader
  paver
Cold Mix
Cold Mix
                      Cold Mix

• Advantages

    High quality coating
      coarse aggregates are fully coated


    Easy to handle
      manufacturing
      hauling
      laying
Cold Mix
Cold Mix
                 Cold Mixes




Core drilling after
     7 days
                Grave emulsion

• Definition
    Dispersion of cationic emulsion
       slow setting
       « soft » bitumen (70/100)


    into a suitable "grave"
       "grave" = coarse gravel
       key points : fines, water content
            Grave emulsion

• Original points

    cold mix

    mortar enriched with soft bitumen
      85% of bitumen contained in 0/6


    internal friction of the aggregates skeleton
                Grave emulsion
• Original behaviour
    friction skeleton
      hardly distorted under quick strain
                                                Variable
    mortar and mastic                          thickness
      possibly distorted under slow strain

    cohesive mix

    workability time, adaptability (storage)
               Grave emulsion

• Key points

    adequate aggregates

      stone type

      grading curve
              Grave emulsion
• Key points : appropriate emulsion (1)
       Adapted to aggregates
         type, % fines, properties, percentage


       Water content                             35-40%

       Base asphalt
         suitable for emulsion
         70/100-180/220
         fluxing? Cut-back?
                Grave emulsion
• Key points : appropriate emulsion (2)
       Grading curve
         homogeneous

       Breaking index                    150-180
       pH>2                  siliceous aggregates
       pH>2.5               limestone aggregates
       Engler pseudo-viscosity            6-12°E
       Temperature               ~30°C and <50°C
              Grave emulsion

• Key points : total water content
    carefully studied

    optimal

    homogeneous

    influence on homogeneity of emulsion dispersion
                 Grave emulsion
• Manufacturing
      Mixing plant : simple and mobile
        sand dosing by weight
        emulsion and water pumps
         – volumetric flow meter (precision <5%)
         – insulated pumps, pipes and tanks
        horizontal paddle mixer
         –   upper position
         –   peripheral paddle speed           2.5 to 3 m/s
         –   water introduction : ahead of mixer
         –   emulsion introduction : 1st third

      Mobile equipment : mixer-finisher
               Grave emulsion
• Transport
    Adequate number of trucks
      based on plant output and laying capacity
    Clean trucks
      no hydrocarbons
    Transport time
      adapted to grave-emulsion type
    Cohesion
      based on outside temperature and hygrometry
    Moistening of support pavement
               Grave emulsion

• Application : no tack coat
    Grader
      often used for leveling and resurfacing
      no single pile
      lateral flanges; working full blade
      discard big chunks

    Paver
      heavy vibrating screed w. heating device
      blade tamper
      leveling beam
                    Leveling


       3cm         4cm
5cm


      Resurfacing + reinforcing


             9cm
Laying with a grader
Laying with a paver




        Paver ABG 411
        Thickness : 8 cm
                Grave emulsion
• Compaction     (New construction works and reinforcement)

    Heavy vibrating roller (>30 kg/cm of generatrix)
      High frequency 30-40 Hz (m.e ~0.7kg.m)
      Low amplitude
      10-15 passes at each point

    Rubber-tyre roller
      3 tons/wheel; 0.7 Mpa; 20 passes each point

    Requirements
      average compaction > 100% test strip
      95% measures > 95 or 97% of average
               Grave emulsion


• Compaction   (Leveling - Resurfacing)

    Rubber-tyre roller
      3 tons/wheel
      0.7 Mpa
      20-25 passes at each point


    Possible addition of light vibrating roller
Compaction


 Steel vibrating roller
                          Tyre compactor
                   Grave emulsion

• Application fields
        New pavements        constant thickness < 12-14 cm
        Reinforcement                         8 to 10-13 cm
        Resurfacing                                  5-13 cm
        Leveling                                 0 to 8-13 cm
        Curing                        3 weeks to 2 months
        Seal coat
    early summer or before         late summer or fall
•
             NO?                          YES?
          New grave emulsions

• Thick layers
    Mixing
        – produces a mastic that becomes the binding component of the
          mixture (similar to hot mixes)
        – mastic    RIGIDITY - COHESION
    Mix cohesion (both volumetric and superficial)
    Elastic modulus
        – mixing, asphalt grade
    Performance in presence of water
•   impact on mix design
       New grave emulsions

• Thick layers
      Different from traditional GE   specific
      applications


• Problem: delayed use
      Transport           increased cohesion
      Layingbreaking; blocks; finisher uneasy
      Compaction
      Sensitivity to climatic conditions
Grave emulsion moduli


     Laboratory studies
  Classical grave-emulsion

   Results of 1994 study
    (Fatigue test LCPC)
      Grave emulsion moduli


   Void      Age      E(MPa)        E(MPa)
content %           15°C – 0.02 s 10°C – 0.02 s
    9.1   +100 days       -          4,000
    9.3   +55 days     2,100         4,000
     -    +6 months    2,850         4,650
     -     +1 year     3,400         5,800
   14.0   +55 days     1,150         2,300
     -    +6 months    1,650         3,350
     -     +1 year     2,200         3,750
   Grave emulsion moduli

              1995 Laboratory studies
            High modulus grave-emulsion


   Void                   E(MPa)          E(MPa)
                Age
content %               15°C – 0.02 s   10°C – 0.02 s


   8         +55 days      4,600           6,500

   8        +6 months      5,700           8,500
   Grave emulsion moduli

              1996 Laboratory studies
            High modulus grave-emulsion


   Void                   E(MPa)          E(MPa)
                Age
content %               15°C – 0.02 s   10°C – 0.02 s


   11        +84 days      5,100           7,100
   Grave emulsion moduli on site

• "Classical" GE for reinforcement
       Age                               4-14 years
       Traffic                              T3 to T1
       Average asphalt content          3.4 to 4.5%
       Ball & ring softening point      44 to 60°C
       Void content                        9 to 15%
       Moduli 10°C - 0.02 s     2,700 to 5,000 MPa
   Grave emulsion moduli on site

• "Enriched" asphalt road base
       Age                        2 months
       Traffic                          T3
       Average asphalt content        4.2%
       Void content                    11%
       Moduli 10°C - 0.02 s      4,800 Mpa
       Moduli 15°C - 0.02 s      3,600 MPa

								
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