What is bitumen MC250?Bitumen MC250 is medium cure bitumen used for binding purposes are usually designated with the letters MC which means medium curing and liquid solvent base bitumen MC250 means viscosity of the bitumen at 60C is minimum 250. The liquid bitumen MC250 is generally blended at the refinery with petroleum fractions such as naptha, kerosene or furnace oils, to yield the desired low viscosity \”cutback grades\” such as those defined hereinbefore.
Reason of low viscosity bitumen MC250?The reduction in viscosity of the bitumen MC250 aids the construction of seal coats in road pavements as the softened mixture wets the chips more easily. The cutback agent evaporates from the seal coat, the cutback agent becoming a negligible component of the seal coat a few months after application. If significant amounts of the cutback agent remain in the seal coat an unwanted long term softening effect may result.
How to choose suitable cutback bitumenThe particular medium cure asphalt used is largely dependent upon ambient temperatures. For example, with warm weather it would be desired to use a medium cure asphalt exhibiting a high viscosity, such as MC800 or MC3000 whereas in cold weather, it would be desired to use a medium cure asphalt exhibiting a low viscosity, such as MC250 or MC70 and bitumen MC30.
Analysis of bitumen MC250
|Kinemalic 1 viscosity at 60°C, eSt||250||500||ASTM D2170|
|Flash Point (Tag Open-Cup),°C||66||–||ASTM D1310|
|Distillate test 2 :|
|Distillate, percent by Volume of total 360°C|
|To 190°C||–||10||ASTM D402|
|To 225°C||15||55||ASTM D402|
|To 260°C||60||87||ASTM D402|
|To 316°C||67||–||ASTM D402|
|Residue from distillation to 360°C:|
|Test on residue from distillation Penetration at 25°C,100g, 5 sec.||30||120|
|Ductility 3 at 25°C, cm||120||250||ASTM D402 / ASTM D113|
|Solubility in trichloroethylene, percent mass||100||–||ASTM D402 / ASTM D2024|
|Water, percent volume||–||0.2||ASTM D95|