Crumb Rubber Modified Bitumen (CRMB)

General Definition of Crmb Rubber Modified Bitumen

Crumb Rubber Modified Bitumen (CRMB) is made by the amalgamation of crumb rubber modifier and the chosen bitumen grade. The modifier works as an agent that strengthens the binder from the occurrence of any deformation when trying to maintain during low temperature, fatigue or thermal issues. CRMB is beneficial as it increases the life of a road by 1.5 to 2 times as to using a normal bitumen modifier.
Crumb Rubber is a worldwide newly developed economic solution enhancing the quality of bitumen used in asphalt mixers for road developments.
(CRMB) is designed to maximize resistance to permanent deformation and to reduce fatigue of asphalt mixtures that are used in most locations.

CRMB provides some unique properties different from bitumen binders like the strong adhesion reduces cracking, deformation, etc. It increases the stability of the material, homogeneity throughout the supply chain.
So, it is very necessary to change Bitumen roads to CRMB for higher resistance, smooth drive, comfort and safety.

Types of Crumb Rubber Modified Bitumen

  • CRMB 60 => Recommended for warm climate
  • CRMB 55 => Recommended for moderate climate
  • CRMB 50 => Recommended for cold climate

steps of produse crumb rubber modified bitumen

The addition of the correct amount of extender oil to the bitumen is normally done at the refinery. Prior to a batch of bitumen rubber being blended, the bitumen is heated to ± 210°C before the rubber crumb is uniformly added using technologically advanced high speed homogeneous mix blender systems. The operator digitally controls the feed of raw materials in precise proportions. Once mixed, it is left for at the reaction temperature for a minimum of 45 minutes prior to application. The complex nature of the blend of hydrocarbons, oils and gels means that its viscosity changes significantly over time at elevated temperatures. Bitumen rubber has a limited shelf-life and is typically blended close to where it will be used or applied.

prcrum rubber modified bitumen

Recommended temperature

Process Temperature Range
Mixing with Aggregates170 - 185°c
Laying150 - 170°c
CompactionOver 140°c
End of Compaction110 - 120°c

Difference Between Using (CRMB) over Conventional Bitumen

Conventional Bitumen Crumb Rubber Modified Bitumen (CRMB)
6 to 8 cm Topcoat Asphalt Thickness5 to 7 cm Topcoat Asphalt Thickness
1 to 5 Years Road Lifetime5 to 15 Years Road Lifetime
High Maintenance CostExtremely Low Maintenance Cost
Low Stability Under High LoadsVery High Stability Under High Loads
Extremely Low FlexibilityExtremely High Flexibility
Moderate Skid ResistanceHigh Skid Resistance
Low Fatigue ResistanceHigh Fatigue Resistance

Advantages of Crumb rubber Modified Bitumen

The advantages of using (CRMB) are well documented worldwide, the major drivers for its use being increased fatigue resistance and reduction in ageing of the binder.
Increased focus on the influence of the construction industry on the environment and ways to reduce and re-use waste material have also motivated the use of crumb rubber modified bitumen.

Application of Crumb rubber Modified Bitumen

  • Stability & Resistance from extreme weather Conditions.
  • Dressing up strong road construction & Development for movement of Heavy Vehicle Movement &
  • High Volume of Traffic.
  • Parking places
  • Bridges and flyovers
  • Procuring From low & High Temperature Cracking of roads.
  • For Making High Load Highways, Junctions, Sea Port, Runway of AirField, Heavy Traffic
  • Movement Roads, etc.

Benefits of (CRMP)

  • The resistance to fatigue is high.
  • It is very cost effective.
  • Strong resistance to thermal and changing temperature cracking.
  • It gives a good experience in extreme climates.
  • Aging process slows down by mixing rubber with bitumen leading to increased lifespan.
  • It gives protection from water damage due to hard grade of asphalt formed.

Packing of (CRMB)

– 180 Kg New Still Drum

Specification of Crumb rubber Modified Bitumen

PROPERTIESCRMB 50CRMB 55CRMB 60
Penetration at 25 ֯C, 1/10mm, 100g, 5 sec< 70< 60<50
Softening Point, (R&B), ֯C, Min505560
Elastic Recovery at 15 ֯C ,%, Min505050
Flash point , COC, ֯C , Min220220220
Separation, Difference in Softening Point,(R&B), ֯C, Max444
Viscosity at 150 ֯C, Poises1-32-63-9
Thin Film Oven Test & Test on Residue_______________
Loss in Mass, %, Max1.0 1.0 1.0
Reduction in Penetration of residue at 25 ֯C , 100g, 5s, %,Max404040
Increase in Softening Point, ֯C, Max765
Elastic Recovery at 25 ֯C, %, Min353535

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