Equivalent standard axial loads

The traffic volume is expressed in equivalent standard (80 kN) axles. The process of converting axial loads into typical axles uses equivalency factors, determined from the equivalence law to the power of 4. The strength of all layers is expressed by their elastic moduli and Poisson ratios. The method also considered environmental temperatures, that is, monthly average air temperatures converted to weighted layer temperature, since they directly affect the stiffness of the asphalt considered in the design. 

The first real-life pavement test undertaken in this sector was the AASHTO road test (HRB 1961, 1962) conducted in the United States from 1957 to 1961. Many different pavement structures, both flexible and rigid, were subjected to traffic loads, and equivalence between loads was established with respect to the load of a standard (or equivalent) axial chosen. 

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