Medium Curing Cutback Bitumen
Medium Curing Cutback bitumen has extensive applications in flexible pavements as surface dressing, prime coating, and tack coating. Solvent evaporation is of medium rate. The grade is mixed with aggregates to enhance the workability of the mix.
The evaporation rate of the medium curing cutback asphalt is referred to as intermediate because kerosene, which is a moderately volatile liquid, is used in comparison to more volatile substances like naphtha and diesel. The degree of liquidity is controlled by the proportion of kerosene mixed with the asphalt cement.
Medium-setting grades are specially formulated to work with aggregates. Since these grades do not break down immediately upon contact with the aggregate, mixtures prepared with them will stay workable over long periods of time and are therefore suitable for cold-mix stockpiles.
The commonly used grades of MC Cutback Bitumen are:
- MC-30
- MC-70
- MC-250
- MC-800
- MC-3000
Applications of MC Cutback Bitumen
MC cutback bitumen is widely used in road construction and maintenance activities due to the equilibrium it offers between workability and curing rate.
One of its most prominent applications is in cold mix asphalt, which is quite convenient when patching and repairing roads in areas where hot mix asphalt is not a viable option. The slow evaporation of the solvent allows the mix to remain workable for extended periods before setting.
The second principal use of MC cutback bitumen is in prime coats, which are applied by spraying on unbound base surfaces before laying asphalt layers. The prime coat helps to stabilize the base and increase the bond between the base and asphalt layer.
Besides, patching of pavement is an effective application of MC cutback bitumen. With a longer workable time, it is suitable for repairing potholes and patching of damaged road sections, especially in remote areas where the hot mix plants are not nearby.
Lastly, MC cutback bitumen is used in surface dressing, a method of enhancing the durability of road surfaces by binding aggregates together. This enhances skid resistance and prolongs the life of roads.
The medium-volatility solvent evaporates after application, leaving the bitumen to form a strong, permanent bond with the surface or aggregates.
