Determination of stiffness modulus and other moduli

The stiffness modulus determination, according to CEN EN 12697-26 (2012), can be carried out with one of the following tests  

All stiffness test methods are considered equivalent and are recommended to be used (CEN EN 13108-20 2008) in specifying asphalt concrete and hot rolled asphalt in terms of fundamental, performance-based properties. 

The tests, apart from (b), are carried out under controlled strain conditions, and all of them are considered to be equally capable in determining stiffness modulus. 

The measurements obtained during any test are applied force, F, in Newtons (N) displacement, z, in millimetres (mm) and their phase angle, b, in degrees (°). 

The two components of the complex modulus, real component Ej and imaginary component 2, when required, are calculated by the following equations  

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