Modern wide-range equations of state for polycrystalline materials behavior description in a wide range of compression parameters include dozens of experimentally defined constants and free variables. Usually it requires to perform multiple cumbersome experiments in order to obtain those required constants for specific materials. Thus, it is necessary to develop construction principles for equations of state with relatively small number of experimentally defined parameters. Such principles are elaborated on the basis of thermodynamic approach and allow implementation of a few-parameter equation of state that only requires parameters available in the handbook of physical quantities. The equation of state for aluminum presented in this paper is a closing relation of viscoelastic Maxwell model. It is formulated as a dependency of specific internal energy from the first and the second invariants of the strain tensor. Numerical and experimental validation demonstrates the applicability of the equation of state and good agreement with experimental data. The validation has been performed for problem of isolation and attenuation of the elastic precursor, and for problem of shock wave propagation and attenuation after interaction with the expansion wave.