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INDUSTRIAL FUEL OIL (LITRE)LHSH- LOW SULPHER HEAVY STOCK (KGFURNCAE OIL (Kg)FOOD GRADE LDO (Litre)LDO-LIGHT DIESEL OIL (Litre)BITUMEN CRMB (BULK)BITUMEN VG-10 (BULK)BITUMEN VG-30 (BULK)BITUMEN VG-40 (BULK)BITUMEN EMULSION RS-1 (BULK)BITUMEN EMULSION SS-1 (BULK)BITUMEN EMULSION MS (BULK)
 

Bitumen CRMB & PMB

National Modified Bitumen (CRMB & PMB)

(Mfd. as per IS 15462:2004 & IRC: SP 53:2002)

 

Description:

Flexible pavements tend to become soft in summer and brittle in winter due to high temperature variations. Also early development of distress symptoms occurs duee to heavy traffic loads on such roads. In these circumstances ordinary bitumen is not sufficient to over come these symptoms.

Modified bitumens are formulated with additives to improve their service performance by changing such properties as their durability, resistance to ageing, elasticity and/or plasticity. Thus altering the physical properties allows bitumen to resist the stress caused by temperature variations, high traffic loads, thereby enhancing pavement life and reducing maintenance costs. The most important modifiers are polymers.

Modified Bitumens are generally categorised into two; Rubber Modified Bitumens and Polymer Modified Bitumens.

Rubber Modifed Bitumens are formulated by using Crumb Rubber or Synthetic Rubber Latex as additives. However Crumb rubber is commonly used.

Polymer Modified Bitumens are formulated by using polymers as additives. Polymers are categorised into two, Elastomeric & Plastomeric.

Plastomeric consists of Polyethylene (PE), Ethylene Vinyl Acetate (EVA),Ethylene Butyl Acrylate (EBA) and Ethylene Ter Polymer (ETP), etc. However Ethylene Vinyl Acetate is commonly used.

Elastomeric consists of Styrene Isoprene Styrene (SIS), Styrene-Butadiene Styrene (SBS) Block Copolymer, etc. However Styrene-Butadiene Styrene is commonly used.

 

Specification of CRMB ( E ) as per IRC SP 53 – 2002 & BIS I5462 – 2004

 

Designation Grades and Requirement Test Method
CRMB 50 CRMB 55 CRMB 60
Penetration at 25°C < 70 < 60 < 50 ISI 203 – 1978
Softening point, (R & B), C Min. 50 55 60 ISI 205 – 1978
Elastic Recovery of half thread in 50 50 50 ISI 5462 – 2004
Flash Point,°C Min 220 220 220 ISI 209 – 1978
Seperation difference in softening point,
(R & B)°C , Max
4 4 4 ISI 5462 – 2004
Thin Film Oven Test (TFOT) on Residue
a. Penetration 25°C , Min % of original 60 60 60 ISI 203 – 1978
b. Increase in softening point,°C, Max 7 6 5 ISI 205 – 1978
c. Elastic Recovery of half thread in 35 35 35 ISI 5462 – 2004
Ductilometer at 25°C , % Min.

Specification of PMB as per BIS I5462 – 2004

Specification / Property Grades and Requirement
PMB 40 PMB 70 PMB 120
Softening Point,°C (min) < 60 < 55 < 50
Penetration at 25°C 30-50 50-90 90-150
Elastic Recovery of half thread, % ( min ) 70 70 70
Seperation, Difference in softening point,°C ( Max ) 3 3 3