MODERN BITUMINOUS BINDERS AND MIXES

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MODERN BITUMINOUS BINDERS AND MIXES

• By
• G.SURESH
• Senior Lecturer
• Department of Civil Engineering
• University Visvesvaraya College of Engineering
• Bangalore University
• Bangalore 560 056

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BINDERS

• BITUMEN
• MODIFIED BITUMEN

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USE OF MODIFIERS IN ROAD CONSTRUCTION

• Bitumen Modifiers
• Modified Bitumen

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ADVANTAGES OF USING MODIFIED BITUMEN

• LOWER SUSCEPTIBILITY TO DAILY AND SEASONAL
  VARIATIONS
• HIGHER RESISTANCE TO DEFORMATION AT HIGH PAVEMENT
  TEMPERATURE
• BETTER AGE RESISTANCE PROPERTIES
• HIGHER FATIGUE LIFE FOR MIXES
• BETTER ADHESION BETWEEN AGGREGATES AND BINDER
• PREVENTION OF CRACKING AND REFLECTION CRACKING

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APPLICATION OF MODIFIED BITUMEN

• Suitable for Renewal Course
• Overlay Material on Surfaces Which are Badly
  Cracked and Subjected to Heavy Traffic
• Used as Stress Absorbing Membrane for Sealing of
  Cracks
• Used at Busy Intersections, Bridge Decks and
  Roundabouts
• Used in Snow Bound Areas

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TYPES OF MODIFIED BINDERS

• Polymer Modified Binders (PMB)
• Natural Rubber Modified Binders (NRMB)
• Rubber Modified Binders (CRMB)

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CLASSIFICATION OF RUBBER AND POLYMER BASED
BITUMEN MODIFIERS
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TESTS ON POLYMER MODIFIED BITUMEN
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TESTS ON CRUMB RUBBER MODIFIED BITUMEN
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THIN/ ROLLING THIN FILM OVEN TEST
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SELECTION OF MODIFIED BITUMEN

• For Cold Climatic Areas
• PMB 120, NRMB 120 and CRMB 50
• For Moderate Climate Areas
• PMB 70, NRMB 40 and CRMB 55
• For Hot Climate Areas and Heavy Traffic Condition
• PMB 40, NRMB 40 and CRMB 60

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ROAD CONSTRUCTED WITH RUBBERISED BITUMEN
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ROAD CONSTRUCTED WITH NORMAL BITUMEN
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RUBBERISED SURFACE DRESSING
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NORMAL BITUMEN SURFACE DRESSING
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SURFACE DRESSING WITH RUBBERISED BITUMEN BINDER
Three years after laying
Shortly after laying
Stone being removed from a surface dressing made
with rubberised bitumen binder
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BITUMINOUS MIXES

• Open Graded Mix
• Dense Graded Mix

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BITUMINOUS MIXES

• DESIRABLE PROPERTIES
• Stability
• Durability
• Flexibility
• Skid resistance
• Workability

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MAIN CONSTITUENTS OF A BITUMINOUS MIX

• Coarse aggregates
• Offer compressive and shear strength and shows
  good interlocking properties
• Material retained on 4.75mm IS sieve is taken as
  Coarse aggregates

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MAIN CONSTITUENTS OF A BITUMINOUS MIX

• Fine aggregates
• Fills the voids in the coarse
• aggregate and stiffens the binder
• Material passing 4.75 mm IS sieve
• and retained on 0.075mm or 75
• micron IS sieve is taken as Fine
• aggregates

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MAIN CONSTITUENTS OF A BITUMINOUS MIX

• Filler
• Fills the voids between the fine
• aggregates, stiffens the binder and
• offers permeability

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MAIN CONSTITUENTS OF A BITUMINOUS MIX

• Binder
• Fills the voids, cause particle
• adhesion

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BITUMINOUS MIX DESIGN

• Mix design is the process of selecting suitable
  ingredients and proportioning their individual
  quantities, to produce an economical end product
  satisfying certain minimum requirements

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BITUMINOUS MIX DESIGN

• The main objective of the mix design is to
  determine the optimum bitumen content to prepare
  a bituminous mix to satisfy following conditions
• Sufficient bitumen to ensure a durable pavement
• Sufficient strength to resist shear deformation
  under traffic at higher temperature

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• Sufficient air voids in the compacted bitumen to
  allow for additional compaction by traffic
• Sufficient workability to permit easy placement
  without segregation
• Sufficient flexibility to avoid premature
  cracking due to repeated loading by traffic
• Not very high stiffness at low temperature to
  prevent shrinkage cracks

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MIX DESIGN METHODS

• Marshall method
• Hveem method
• Hubbard-Field method
• Smith Tri-axial method

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DESIGN OF BITUMINOUS MIX BY MARSHALL METHOD

• Selection of Aggregate
• Selection of Aggregate Grading
• Proportioning of Aggregates
• Determination of Specific Gravity

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• Preparation of Specimen
• Determination of Specific Gravity of Compacted
  Specimen
• Density Void analysis
• Stability- Flow Tests on Compacted Specimens
• Selection of Optimum Bitumen Content

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PREPARATION OF MARSHALL SPECIMENS

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MARSHALL STABILITY TEST
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MARSHALL STABILITY TEST
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• DETERMINATION OF OPTIMUM BITUMEN
• CONTENT CORRESPONDING TO
• Maximum Stability
• Maximum Unit Weight
• 4 Air Voids in Total Mix

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DETERMINATION OF OPTIMUM BITUMEN CONTENT
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THANK YOU