What is Slow Curing Cutback Bitumen?
Slow Curing (SC) Cutback Bitumen is asphalt cement that has been blended with a low-volatility petroleum solvent, such as diesel or fuel oil, to reduce its viscosity so that it can be more easily spread. “Slow curing” refers to the slow evaporation of the solvent, which allows for a setting time longer than with medium or rapid curing cutbacks. This characteristic makes SC cutback bitumen particularly well suited for use in stockpile mixes and cold mix applications where extended workability is needed.
The most popular grades for SC Cutback Bitumen are:
- SC-70
- SC-250
- SC-800
- SC-3000
These are the references to the kinematic viscosity of the bitumen in centistokes (cSt). The solvent concentration in SC cutback bitumen is typically in the range 5-25% of the total volume of asphalt cement used.
Applications of Slow Curing Cutback Bitumen
Slow Curing Cutback Bitumen is used in several applications. Common uses include penetrating prime coats and producing patching or stockpile mixtures. When mixed with aggregate, it often contains an adhesion agent to help coat the aggregate surface effectively.
Furthermore, cutback agents reduce the viscosity of bitumen, making it easier to apply as a primer on road pavements or base courses. For instance, kerosene is a common cutback agent used at varying concentrations, depending on local conditions and requirements.
In addition, Slow Curing Cutback Bitumen is ideal for prime coats and cold applications. It’s easy to use, as it doesn’t require thinning or heating. For construction, the initial application of cutback bitumen forms a strong bond between asphalt and the non-asphalt-based course. It can also be used for waterproofing surfaces by sealing capillary voids and bonding loose mineral particles.
Slow Curing Cutback Bitumen is typically applied in penetrating prime coats and patching or stockpile mixtures. When it is combined with aggregate, an adhesion additive is introduced to enhance the coating of aggregate surfaces to enable it to form a stronger bond and lasting pavement.
In addition, cutback agents reduce the viscosity of bitumen so that it becomes easier to apply as a road pavement primer or base course. One of the most widely utilized cutback agents is kerosene, used in varying proportions depending on climate and local construction requirements.
Slow Curing Cutback Bitumen is similarly effective for use in cold climates, as it does not have to be heated or thinned before application. In construction on buildings, the initial application creates a firm bonding between asphalt and the underlying non-asphalt ground. It is also effective as a waterproofing agent, capping capillary voids and binding loose mineral particles to create a more resistant and durable weather surface.
Summary
Slow Curing Cutback Bitumen is an essential material in road construction. It improves the application of bitumen in varying environmental conditions and construction processes. Thanks to its adaptability, it serves as a vital component in creating durable road surfaces and coatings. By choosing the appropriate grade of cutback bitumen, construction operations can achieve the desired consistency and quality.
