AS PER IRC:SP:53- 2002 & IS 15462:2004 (lSI MARKED)


This invention relates to the process for the preparation of a Polymer and Rubber based modified binder, which is usefulfor the construction of roads catering to heavy traffic and also for the formation of airfields surfacing, besides its use as binder for stress absorbing membrane (SAM) and stress absorbing membrane interlayer (SAMI) for sealing of cracks, preventive maintenance of flexible pavement and delaying reflective cracking.

Modified bitumen performs better than ordinary bitumen in high rain fall area and in situations where the aggregates are prone to stripping. Flexible pavements constitute major portion of existing road network and airfields in India.An extensive highway network with desired high speed corridors and air-fields constructed with long lasting pavement and overlays are felt essential.The growth of the economy of a country depends largely upon efficient transport system with minimal possible hindrance to road user due to frequent maintenance needs. The quality and longevity of pavement as well as overlays and renewals must be, therefore restored in order to reduce road user cost and achieve road safety.Increased number of traffic loads with over loading in excess of permissible limits, higher tyre pressure have caused widespread problems with flexible pavement of National highways.The available 80/100, 60/70 or 30/40 grade or VG grade bitumen produced at our refineries are not suitable for high traffic intensity roads and airfield pavement due to extremely high tyre pressure of aircrafts.The statistics of various overlay I renewals performance suggested that useful life of bituminous overlay has declined from an average value of 8-10 years in the past to about 3-4 years in recent years. Hence under the prevailing heavy traffic and extreme climatic conditions, conventional overlays, in general are not meeting durability requirement. The accelerated deterioration of flexible pavement overlays or renewals prematurely, burdens the maintenance budget and poses fund's constraints on using binders, which act as multigrade binders and also offer resistance to deformation and cracking. The binders should also enable the pavement to have longer fatigue life to resist the repeated application of high axle loads and prevent cracking or reflective cracking. Research carried out on the available bitumens from Indian refineries indicated that these are not suitable for airfields catering to Boeing 747 class or A380 of aircraft.It is also well known that, if polymer in a small quantity when added to 80/100, 60/70 or 30/40 grade VG grade bitumen, result in a product, which has a fatigue life 10-18 times higher than conventional 80/100,60/70 or 30/40 grade VG grade bitumen.This binder is also found to be capable to seal cracks effectively, when applied over extensively cracked flexible or rigid pavement. Plastomeric thermoplastic based modified bitumen are not considered suitable for SAM & SAMI. Extensive road trials conducted by CRRI and elsewhere globally proved that life of road can be extended 50 to 100% times, resulting in enormous savings in pavement materials and funds.

Polymer and Rubber modified binders are classified as per type of modifier as under:

# Examples
1 Synthetic Polymers Polyethylene (PE), Ethylene Vinyl Acetate (EVA),Ethylene ButylAcrylate (EBA) and Ethylene Ter Polymer (ETP), etc.
Styrene Isoprene Styrene (SIS), Styrene-Butadiene Styrene (SBS) Block Copolymer, etc.
2 Synthetic Rubbers Styrene-Butadiene Rubber (SBR) latex and any other Suitable synthetic Rubber
3 Other Rubbers Latex or Rubber Powder
Crumb Rubber Modifier
The specific Improvements of nkl Polymer and Rubber modified Bitumen produced by this new process are as under:-
  • Polymer and Rubber Modified Bitumen improves resistance to cracking, resulting in stronger and more durable overlays for corridors in the areas of extreme climatic conditions and heavy traffic loads.
  • It reduces deformation on road, this is specifically true at elevated temperature (50°C to 70°C), where rutting is excessive. It is achieved due to improved viscosity and elastic recovery of polymer and rubber based modified bitumen, compared to conventional bitumen.
  • Promote binder adhesion and cohesion to mineral aggregates
  • The stripping level and ravelling of aggregates from surface are reduced and offer resistance to creep deformation.
  • Low temperature brittleness properties of bitumen in pavement due to excessive ageing are improved as evident from improved ductility and elastic recovery values at low temperature.
  • Polymer & Rubber based modified binder extend life of pavement by 50% to 100%, when compared to conventional bitumen overlays or renewal as proved by field trials.
  • Polymer & Rubber based modified binders act as multigrade bitumen and are economical, when life cycle cost is taken into consideration.It can be used as membrane overlays for preventive rnaintenance of pavement.

Easy to Use:

Polymer and Rubber Modified Bitumen can be used in the construction, maintenance and renewal of roads, airfields and heliports in a manner similar to the existing hot mix process using the same manpower, tools and plant.

Selection Criteria for PMB,NRMB and CRMB based on atmospheric temperature.

                                                     Maximum Atmospheric Temperature,°C

Minimum Pravement Temperature, °C
<35 35 TO 45 >45
-10 To 10 PMB/NRMB-70 CRMB-55 PMB/NRMB-40 CRMB-60



Designation Elastomeric Thermoplastic Based Plastomeric Thermoplastic Based Natural Rubber Modified Binders Crumb Rubber Modified Binders Merthod of tests
  PMB 120 PMB 70 PMB 40 PMB 120 PMB 70 PMB 40 NRMB 120 NRMB 70 NRMB 40 CRMB 50 CRMB 55 CRMB 60  
Penetration at 25°C, 0.1mm,100g.5 Sec 90 to 150 50 to 90 30 to 50 90 to 150 50 to 90 30 to 50 90-150 50-90 30-50 <70 <60 <60 IS: 1203-1978
Saftening Point (R&B)°C Minimum 50 55 60 50 55 60 50 55 60 50 55 60 IS:1205-1978
Ductility at 27°C cm. +75 +60 +50 +50 +40 +30 +75 +60 +50 - - - IS:1208-1978
Fraass Breaking Point°C Max -24 -18 -12 -20 -16 -12 -20 -16 -12 - - - IS:9381-1979
Flash Point by COC°C Minimum 220 220 220 220 220 220 220 220 220 220 220 220 IS:1209-1978
Elastic Recovery of Half Thread in Ductilometer at 15°C, %, Min 75 75 75 50 50 50 50 40 30 50 50 50 Appendix-1 IRC:SP:53 2002
Separation Differnce in softening Point R&B°C, Maximum 3 3 3 3 3 3 4 4 4 4 4 4 Appendix-2 IRC:SP:53 2002
Viscosity at 150°C poise 1-3 2-6 3-9 1-3 2-6 3-9 - - - - - - IS:1206-1978
Thin Film Oven Test (TFOT) on Residue (IS:9382-1992)
Loss in Weight, %, Maximum 1.0 1.0 1.0 1.0 1.0 1.0 - - - - - - IS:9382-1979
Increase in Softening Point °C, Maximum 7 6 5 7 6 5 7 6 5 7 6 5 IS:12QS.1978
Reduction in Penetration of Residue at 25°C, Maximum 35 35 35 35 35 35 - - - - - - IS:1203-1978
Penetration at 25°C 0.1 mm, 100g, 5 Sec. Minimum % of original - - - - - - 60 60 60 60 60 60 IS:1203-1978
Elastic Recovery of Half thread in Ductilometer at 25°C, % Minimum 50 50 50 35 35 35 35 30 25 35 35 35 Appendix-1 IRC:SP:53 2002
*Relevant to snow bound cold dlmate area.
•we also manufacture Modified Bitumen as per IS:15462:2004