Medium Curing Cutback
MEDIUM CURING CUTBACK (MC)
Asphalt cutbacks use petroleum solvents for dissolving asphalt cement. The solvents are variously called distillate, diluents or cutter stock. If the solvent used in making the cutback asphalt is highly volatile, it will quickly escape by evaporation. Solvents of lower volatility evaporate more slowly. On the basis of the relative speed of evaporation, cutback asphalts are divided into three types: rapid curing (RC), Medium Curing Cutback and slow curing (SC). Medium Curing Cutback is a compound of different oil solvents such as kerosene in order to transform bitumen to soluble bitumen which is evaporated in oil solvent using process and the bituminous layer is remained to make cohesion, penetration and form a sealing layer. A famous sort of it known as MC250 or liquid bitumen in asphalt section including pavement (cohesive between 2 Tack coat asphaltic layers), cold asphalt (Roadmix) and substructure (cohesive between asphaltic and soil layers-Prime coat) has been previously using in Iran. Available kerosene in MC250 would lead to promoting bitumen restoration, better penetration in infrastructure application (Primecoat) but yet will increase environmental hazards, price and heating cost in using and discharging time comparison with various types of water-based emulsions. Bitucut bitumen is produced and supplied in these types: MC800, MC250, MC70, MC30 and MC3000 which have the different percentage of solvent. Bitucut usage differs in various conditions such as substructure (continuous grading with low free space, open grading, and soil percentage). Medium curing (MC) asphalt cement uses medium diluents of intermediate volatility generally in the kerosene boiling point range ( 30, 70, 250, 800, 3000 ). The degree of liquidity developed in each case depends principally on the proportion of solvent to asphalt cement. To a minor degree, the liquidity of the cutback may be affected by the hardness of the base asphalt from which the cutback is made. The degree of fluidity results in several grades of cutback asphalt—some quite fluid at ordinary temperatures and others somewhat more viscous. The more viscous grades may require a small amount of heating to make them fluid enough for construction operations. The medium setting grades are designed for mixing with aggregates. Because these grades do not break immediately upon contact with aggregate, mixes using them can remain workable for extended periods of time and lend themselves to cold mix stockpiles.
MEDIUM CURING CUTBACK BITUMEN USAGE
The medium curing cutback bitumen is used in the flexible pavements for surface dressing, prime coating, and tack coating. The evaporation of the solvents will be at a moderate rate. This grade is used with aggregates for ensuring better workability in the mix. The degree of evaporation in the medium curing cutback asphalt is intermediate because the kerosene is intermediate volatile liquid as compared to the naphtha and diesel. The degree of liquidity depends on the proportion in which the kerosene is mixed in the asphalt cement. The medium-setting grades are designed for mixing with aggregates. Because these grades do not break immediately upon contact with aggregate, mixes using them can remain workable for extended periods of time and lend themselves to cold mix stockpiles. The degree of liquidity developed in each case depends principally on the proportion of solvent to asphalt cement. To a minor degree, the liquidity of the cutback may be affected by the hardness of the base asphalt from which the cutback is made. The degree of fluidity results in several grades of cutback asphalt—some quite fluid at ordinary temperatures and others somewhat more viscous. The more viscous grades may require a small amount of heating to make them fluid enough for construction operations. The medium-setting grades are designed for mixing with aggregates. Because these grades do not break immediately upon contact with aggregate, mixes using them can remain workable for extended periods of time and lend themselves to cold mix stockpiles.
APPLICATION OF MEDIUM CURING CUTBACK
Similar to emulsified asphalts, after a cutback asphalt is applied the petroleum solvent evaporates leaving behind asphalt cement residue on the surface to which it was applied. Cutback asphalt is said to “cure” as the petroleum solvent evaporates away. The use of cutback asphalts is decreasing because of environmental regulations. Medium curing cutback bitumen, which is a type of bitumen diluted with a volatile solvent, is commonly used in various applications. The specific application can depend on factors such as climate, construction requirements, and the desired curing time.
HERE ARE SOME COMMON APPLICATION OF MEDIUM CURING CUTBACK BITUMEN:
- Road Construction: Medium curing cutback bitumen is widely used in road construction for preparing bituminous mixes. It is applied as a prime coat or tack coat to enhance the bond between the existing road surface and the new asphalt layer.
- Surface Dressing: This type of cutback bitumen is suitable for surface dressing applications. It is sprayed on the road surface to provide a waterproof layer and improve the durability of the road.
- Prime Coating: Medium curing cutback bitumen is commonly used as a prime coating in road construction. It helps in preparing the base surface by providing a thin adhesive layer for better adhesion of subsequent asphalt layers.
- Tack Coat: It serves as a tack coat, promoting adhesion between asphalt layers during pavement construction. The tack coat ensures that the layers adhere well to each other, enhancing the overall stability of the pavement.
- Patchwork: Medium curing cutback bitumen is used for patchwork and repair of damaged road sections. It helps in sealing the repaired area and preventing moisture ingress.
- Dust Control: In regions where dust control is a concern, medium curing cutback bitumen can be applied to gravel or dirt roads. This helps in stabilizing the surface and reducing dust emissions.
- Construction of Parking Lots: Medium curing cutback bitumen is used in the construction of parking lots, providing a durable and weather-resistant surface.
- Temporary Pavements: It can be employed in the construction of temporary pavements for events or construction sites where a quick curing process is required.
It’s important to follow industry standards and guidelines when using medium curing cutback bitumen to ensure proper application and performance. Additionally, the choice of cutback bitumen grade may vary based on specific project requirements and environmental conditions. Manufacturers and suppliers typically provide technical specifications and recommendations for their products.
TECHNICAL DATA SHEET OF MC-30
| Property | Min | Max | Test method |
|---|---|---|---|
| Kinematic viscosity at 60°c ,cST | 30 | 60 | ASTM D2170 |
| Flash point(tag open cup), °C | 38 | - | ASTM D3143 |
| Viscosity at 140°F (60°C) | 30 | 120 | ASTM D2170 |
| Penetration 77°F (25°C) 100g,5s mm | 120 | 300 | ASTM D5 |
| Ductility 77°F (25°C) 5cm/min cm | 100 | - | ASTM D113 |
| Solubility in trichloroethylene % | 99 | - | ASTM D2042 |
| Water, percent volume | - | 0.2 | ASTM D95 |
TECHNICAL DATA SHEET OF MC-70
| Property | Min | Max | Test method |
|---|---|---|---|
| Kinematic viscosity at 60°c ,cST | 70 | 140 | ASTM D2170 |
| Flash point(tag open cup), °C | 38 | - | ASTM D3143 |
| Viscosity at 140°F (60°C) | 30 | 120 | ASTM D2170 |
| Penetration 77°F (25°C) 100g,5s mm | 120 | 300 | ASTM D5 |
| Ductility 77°F (25°C) 5cm/min cm | 100 | - | ASTM D113 |
| Solubility in trichloroethylene % | 99 | - | ASTM D2042 |
| Water, percent volume | - | 0.2 | ASTM D95 |
TECHNICAL DATA SHEET OF MC-2500
| Property | Min | Max | Test method |
|---|---|---|---|
| Kinematic viscosity at 60°c ,cST | 250 | 500 | ASTM D2170 |
| Flash point(tag open cup), °C | 66 | - | ASTM D3143 |
| Viscosity at 140°F (60°C) | 30 | 120 | ASTM D2170 |
| Penetration 77°F (25°C) 100g,5s mm | 120 | 300 | ASTM D5 |
| Ductility 77°F (25°C) 5cm/min cm | 100 | - | ASTM D113 |
| Solubility in trichloroethylene % | 99 | - | ASTM D2042 |
| Water, percent volume | - | 0.2 | ASTM D95 |
TECHNICAL DATA SHEET OF MC-800
| Property | Min | Max | Test method |
|---|---|---|---|
| Kinematic viscosity at 60°c ,cST | 800 | 1600 | ASTM D2170 |
| Flash point(tag open cup), °C | 66 | - | ASTM D3143 |
| Viscosity at 140°F (60°C) | 30 | 120 | ASTM D2170 |
| Penetration 77°F (25°C) 100g,5s mm | 120 | 250 | ASTM D5 |
| Ductility 77°F (25°C) 5cm/min cm | 100 | - | ASTM D113 |
| Solubility in trichloroethylene % | 99 | - | ASTM D2042 |
| Water, percent volume | - | 0.2 | ASTM D95 |
TECHNICAL DATA SHEET OF MC-3000
| Property | Min | Max | Test method |
|---|---|---|---|
| Kinematic viscosity at 60°c ,cST | 3000 | 6000 | ASTM D2170 |
| Flashpoint(tag open cup), °c | 66 | - | ASTM D3143 |
| Distillation test Distillate, volume percent of total Distillate to 680°F (360°C) | |||
| to 437°F (225°C) | - | - | ASTM D402 |
| to 500°F (260°C) | - | 15 | ASTM D402 |
| to 600°F (316°C) | 15 | 75 | ASTM D402 |
| Residue from distillation to 680°F (360°C), percent volume by difference | 80 | - | ASTM D402 |
| Test on Residue from distillation test | |||
| Viscosity at 140°F (60°C) | 30 | 120 | ASTM D2170 |
| Penetration 77°F (25°C) 100g,5s mm | 120 | 300 | ASTM D5 |
| Ductility 77°F (25°C) 5cm/min cm | 100 | - | ASTM D113 |
| Solubility in trichloroethylene % | 99 | - | ASTM D2042 |
| Water, percent volume | - | 0.2 | ASTM D95 |
