DRK Infratech

Crumb Rubber Modified Bitumen

Conforming to IS: 15462 & IRC: SP: 53

Starmac - CRMB is a Crumb Rubber based Modified Bitumen produced by mixing crumb rubber and other additives which are compatible with bitumen.

Starmac - CRMB, which is Crumb Rubber Modified Bitumen, is prepared in a centrally located state-of-the-art plant equipped with special high shear mixing facility, the first of its kind in South India. Starmac - CRMB has been specially designed after extensive research to meet the requirements of high traffic intensity, increasing axle loads, and varying climatic conditions of our country.

Starmac - CRMB is the ideal binder to overcome the concurrent problems of raveling, rutting, un-dulations, cracking, bleeding, shoving and pot-holing of bituminous pavement.


Starmac - CRMB is available in following grades

  • Starmac CRMB 50
  • Starmac CRMB 55
  • Starmac CRMB 60


  • Excellent Resistance to thermal and low temperature cracking.
  • Superior resistance to any form to permanent deformation.
  • Better adhesion between aggregate and binder.
  • Overall improved performance in extreme climatic conditions.
  • Delay of cracking and reflective cracking.
  • Susceptibility to daily and seasonal temperature variations.
  • High Marshall stability.
  • Does not require change in construction practices/ machinery.
  • Cost effective.


Bituminous mix, prepared with STARMAC has a higher stifness modulus, enhanced fatigue life, better resistance to creep & higher indirect tensile strength and quite suitable as renewal course and overlay materials on surface which are badly cracked and subjected to heavy traffic.

  Starmac 50 Starmac 55 Starmac 60 IS No.
Peneration at 25 Cm 0.1 mm, 100 g, 5s <70 <60 <50 1203
Softening point (R&B), 0C, Min 50 55 60 1205
Flash point, COC, 0C, Min 220 220 220 1209
Elastic recovery of half thread in
ductilometer at 150 C, percent Min
50 50 50 Appen.1 of IRC:SP:53-2002/
Annex.A of IS 15462:2004
Separation, difference in softening point
(R&B), C, Max
4 4 4 Appen.1 of IRC:SP:53-2002/
Annex.B of IS 15462:2004
Viscosity at 1500 C, Poise 1-3 2-6 3-9 1206(PART 2)
Thin film oven test and tests on residue        
Loss in mass, percent, Max 1.0 1.0 1.0 9382
Increase in softening point 0C, Max 7 6 5 1205
Reduction in penetration at 250 C Max 40 40 40 1203
Elastic recovery of half thread at 250 C Min 35 35 35 Appen.1 of IRC:SP:53-2002 /
Annex.A of IS 15462:2004

Choice of Starmac - CRMB

Starmac-CRMB is recommended for roads with heavy intense traffic and also for extreme climatic conditions.

Starmac - CRMB performs better than normal bitumen in high rainfall areas and in situations where the aggregates are prone to stripping. Due to its better creep resistance properties, Starmac - CRMB can also be used at busy intersections, bridge decks, and round-abouts for increased life of surfacing. Starmac - CRMB also finds useful applications in porous asphalts.

The selection of the grade of Starmac - CRMB will be based on traffic intensity and climate conditions as given below:

Quality Assurance

Starmac - CRMB is produced in a state of the art central plant with a high shear machine as per the guidelines laid down by IRC: SP: 53 and Indian Standard IS: 15462 specifications for Polymer & Rubber Modified Bitumen. Starmac - CRMB is available in bulk as well as packed drums.

Selection Criteria for Starmac - CRMB

Minimum Pavement Temperature C

Minimum Atmospheric Temperature, 0C
  <35 35-45 >45
10 to -10 STARMAC 50 STARMAC 55 STARMAC 60

* Not below 15 C

Temperature of mixing and rolling shall be slightly higher than conventional bituminous mixes.

The Broad range of temperature at different stage is as follows:

Stage of work Indicated temperature 0C
Binder at mixing 165-185
Mix at mixing plant 140-160
Mix at laying site 130-150
Rolling at laying site 115-135

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