What is the penetration grade of blown asphalt?

Blown asphalt, also known as oxidized asphalt, undergoes a process where air is introduced at high temperatures, resulting in a stiffening of the asphalt binder. This modification increases its viscosity and enhances certain properties, making it suitable for various applications like roofing and waterproofing.

The penetration grade refers to a measure of the hardness of asphalt and is determined by the depth (in tenths of a millimeter) to which a standard needle penetrates the asphalt under specific conditions of load, time, and temperature. For blown asphalt, the typical penetration grades range between 0 to 30, indicating that it is significantly stiffer and harder than conventional asphalt grades.

Answering with 0 to 30 penetration grade accurately reflects the properties of blown asphalt, as it characterizes the higher viscosity and reduced penetrability that result from the oxidative process. This information is crucial for engineers when selecting materials for specific applications, ensuring that the functionality and durability requirements are met in construction and engineering projects.