Cutback Bitumen

We have in store for our clients, Cutback Bitumen, which is developed as per the IS standards. Clients can avail cut-back bitumen of RC-3, MC-3, and MC-5 grades for cold weather construction and maintenance under all weather conditions. It is a free flowing liquid at normal temperatures. The cut-back bitumen we are offering is obtained by fluxing bitumen with suitable solvents. Its viscosity is substantially reduced by adding Kerosene or any other solvent. Further, Cut-back is used in tack coat applications and its various grades are available in India, which are governed by IS: 217:1988 standards.

Types and grades:

Cut-back Bitumen shall be of three types:

• Rapid Curing (RC)
• Medium Curing (MC)
• Slow Curing (SC)

Tests for Cut-Back Bitumen:

Viscosity:

• A standard test as specified in IS:1206-1978 Part-I
• For Cut-Back Bitumen, a standard tar viscometer (STV ) of 4 mm diameter orifice is used
• The grade of Cut-back bitumen is designated by its viscosity value

Flash Point:

• This standard test is specified in IS : 1209-1978
• For Cut-Back Bitumen, flash Point in ° C is determined by Penske Martens closed cup apparatus
• The value signifies the safe temperature to which cut-back bitumen can be heated

Distillation:

• A standard test specified in IS:1213-1978
• In this test volatile constituents Cut back bitumen are separated between different specified temperature ranges
• From this, the type of cut back bitumen can be identified
• The type and quantity of distillate controls the curing time of cut back bitumen
• Cut back bitumen RC-3 is obtained by blending paving bitumen 80/100 with about 16 percent by weight of naphtha type distillate requires approximately 12 hours of curing time
• A cut back bitumen is taken as cured when the float value at 50° C is more than 120 seconds
• The details of float test are given in IS: 1210-1978
• Residue obtained from the distillation test is tested for penetration and ductility to determine the nature of base bitumen used in preparation of cut-back bitumen

Procedure For Field Preparation Of Cut Back Bitumen:

Paving Bitumen 80/100 is heated at 100° to 110°in a bitumen boiler. The required quantity of distillate of specified type is taken in an empty drum. Hot bitumen from the boiler is added to the drum. After closing the lid of the drum containing distillate and hot bitumen, it is rolled on the ground to and fro till a uniform blend is obtained. The blend so prepared is transferred to a storage tank. Sufficient quantity of cut back bitumen has to be prepared before undertaking the road construction work. It may be ensured that the drum containing distillate is kept at a safe distance from bitumen boiler equipment.