Medium Curing Cutbacks
Asphalt cutbacks are produced during the refining process or from heated asphalt cement that is cut-back with a volatile petroleum distillate (cutter stock).In contrast to AC, asphalt cutback is workable a low temperatures. Naptha, gasoline, kerosene, jet fuel, diesel oil, and fuel oil can be used as the cutter stocks.Three types of cutbacks are named based on their rate of curing. Medium curing asphalt cutbacks (MC) contain a less volatile substance such as kerosene or jet fuel.Upon exposure to the atmosphere, the diluents evaporate, leaving the asphalt remaining to perform the function of cementing or waterproofing.
MC cutbacks are popular for sealant purposes, prim and tack coats, crack filling, and for mixing with gravel to patch holes in pavement.
The viscosity (resistance to flow) of asphalt cutback varies according to the amount of cutter stock added and the type of AC used. As the amount of cutter stock increases,the viscosity decreases. Each type of asphalt cutback is produced in standard grades of kinematic viscosity (30, 70, 250, 800, and 3000 centistokes). The numerical grade is the lowest kinematic viscosity limit at 140*F, and the upper limit is twice the lower limit.
This product is typically referred to as 'Prime Oil'. This grade is used for priming dusty roads in preparation of paving.
|Type and Grade||Min.||Max.|
|Kinematic Viscosity at 140*F, cSt||30||60|
|Flash Point (TOC), *F||100||...|
|Flash Point (COC), *F||...||...|
|Distillation test to 437*F||0||25|
|Distillation test to 500*F||40||70|
|Distillation test to 600*F||75||93|
|Residue from distillation to 680*F||50||...|
|Vacuum viscosity at 140*F||300||1200|
|Ductility 5cm/min, cm.||100||...|