We are going to talk about WSDOT asphalt binder course types reference cost grades today. Asphalt binder or asphalt liner is used for underlying. This asphalt has broken stones and is larger than Topeka asphalt, and it is used under it to prevent movement and displacement of the road and street surface. However, we are going to talk about its other aspects like its course, types, references, and grades.

Asphalt binder course

An asphalt binder course is a layer of asphalt concrete that is placed directly on top of the base course layer in a roadway construction project. A "binder layer" is another name for it. In addition to providing a smooth surface for the wearing course layer, the binder course serves as a barrier to stop moisture from accessing the base course layer.

The aggregate in the asphalt binder course is often coarser than the aggregate in the base course layer because it is made up of a combination of asphalt binder and aggregate. The binder course layer might be any thickness between 2 and 4 inches, depending on the exact project needs.

Heating the asphalt binder to a liquid condition and combining it with the proper aggregate are the steps involved in putting down an asphalt binder course. After that, the mixture is brought to the building site and laid using an asphalt paver. After that, the surface is compressed to make it solid and homogenous, improving its resistance to abrasion.

In general, the asphalt binder course is crucial in ensuring a firm and long-lasting highway surface that can bear vehicle weight and traffic.

Asphalt binder types

Asphalt binders are materials used in the construction of roads and other paved surfaces. They generally consist of asphalt cement and a variety of aggregates, and they provide both automobiles and pedestrians with a sturdy, weather-resistant surface. 

 Asphalt binders come in a variety of forms that may be categorized according to their performance traits and physical attributes. Some of the most typical varieties can be listed below :

 Penetration-Graded Asphalt Binders: These are often used in the building of conventional roads and are categorized according to their penetration rates, which represent the depth to which an ordinary needle will pierce the asphalt binder at a certain temperature

 Performance-Graded Asphalt Binders: These are categorized according to their performance characteristics, such as their resistance to rutting and cracking. They are often utilized in high-stress settings including airports and robust industrial settings

 Polymer-Modified Asphalt Binders: Polymers are added to these to enhance their performance qualities, including their resistance to cracking and deformation. They are often employed in locations with a lot of traffic and big loads

 Emulsified Asphalt Binders: These are manufactured by creating a stable liquid by mixing asphalt cement, water, and an emulsifying agent. They are often used as tack coats for layers of asphalt pavement and surface treatments

 Cutback Asphalt Binders: These are created by reducing the viscosity of asphalt cement by cutting or dilution. They are often used as a primer coat for asphalt pavement layers and in surface treatments.

WSDOT asphalt binder reference cost

Let's talk about the WSDOT asphalt binder reference cost now.

The Washington State Department of Transportation (WSDOT) has a standard for the asphalt binders they utilize in their pavement construction projects. By this standard, asphalt binders must meet certain requirements to be used on WSDOT projects.

The specifications of either the AASHTO M320 or ASTM D6373 standard shall be met by the asphalt binder used in WSDOT projects, according to the WSDOT Asphalt Binder standard. Additionally, the following conditions must be met by the asphalt binder:

The asphalt binder's viscosity at 135°C (275°F) should be between 75 and 250 poises.

At a temperature of 25°C (77°F), the asphalt binder's penetration value should range from 40 to 120 Deci millimeters (dm).

The asphalt binder's ductility at 5 °C (41 °F) should be more than 100 cm.

A good asphalt binder should have a flash point of at least 232°C (450°F).

There should be more than 99.0% mass solubility of the asphalt binder in trichloroethylene.

The WSDOT Asphalt Binder Specification also includes specifications for the asphalt binder's other characteristics, including its elastic recovery, softening point, and aging index. These characteristics are utilized to make sure that the asphalt binder is of sufficient quality for use in WSDOT projects and will function suitably over time. Regarding its cost, I have to say that it is being changed in specific periods.

Asphalt binder grades

Asphalt binders are categorized into different grades based on their physical properties, which are identified by testing in laboratories. The viscosity of the binder at a specified temperature is often the basis for the grading system for asphalt binders.

The Performance Graded (PG) System and the Viscosity Graded (VG) System are the two most used grading systems for asphalt binders in the US.

The Strategic Highway Research Program (SHRP) created the Performance Graded (PG) System, which is used to designate asphalt binders based on their performance characteristics at various temperatures. The asphalt binder will function well at two different temperatures, one at high temperatures (PG "X") and the other at low temperatures (PG "Y"), according to the PG System. A PG 64-22 asphalt binder, for instance, performs best at 64°C for hot temperatures and at -22°C for low temperatures.

The Viscosity Graded (VG) System is based on the asphalt binder's viscosity at 60 degrees Celsius. The asphalt binder's viscosity range is denoted by numbers in the VG System. A VG 30 asphalt binder, for instance, has a viscosity range of 2400–3600 centistokes at 60 °C.

Other grading systems for asphalt binders exist in addition to the PG and VG systems; some are employed in certain areas or for particular purposes. One such system is the Superpave Performance Graded (PG) System, which is used for high-traffic asphalt pavement applications in the United States.