AASHTO M 320-21 PDF Download

AASHTO M 320-21 is a standard specification that pertains to the grading and performance evaluation of asphalt binders. The grading designations are determined based on the maximum and minimum pavement design temperatures, which helps in selecting the appropriate binder for different climate conditions.

The specification includes two tables, namely Table 1 and Table 2. By default, Table 1 is used if no specific table is mentioned. Table 2 incorporates the use of R 49, which is a method to determine the critical low cracking temperature. This determination is made by using a combination of test procedures T 313 and T 314.

It is important to note that if the viscosity at 60°C is used for grading asphalt cements, the specifications provided in M 226 should be followed. Additionally, the standard provides guidance on how to determine the performance grade of an asphalt binder using the information provided in R 29. For specifying performance-graded asphalt binder using Multiple Stress Creep Recovery (MSCR), the specifications in M 332 should be referred to.