Numerical-experimental methodology to study the viscous behavior of ceramic materials and to determine the material viscosity as a function of temperature, comprising the steps of: (i) producing a significant number of material specimens to be used for a bending experimental tests with an optical instrument; (ii) carrying out the bending experimental test in which the material specimen, loaded at least by its own weight, undergoes thermal and viscous deformations and measuring the vertical displacement in the specimen midpoint as a function of temperature; (iii) deriving, starting from said experimental test, a bending curve and a bending rate curve in the specimen midpoint; (iv) repeating the bending experimental test for a significant number of specimens in order to verify the results repeatability; (v) defining an equation to calculate the material viscosity by using the bending rate curve, δ ̇ x = 0 *: η = 5 ⁢ ρ g L * 4 32 ⁢ δ ̇ x = 0 * ⁢ h * 2 where g is the gravity acceleration, p the material densification curve, L* and h* are, respectively, the span and the section height of an equivalent beam that, in the two points bending configuration test, deforms with the same bending rate, δ ̇ x = 0 *, of the C shaped specimen, (vi) performing FEM numerical analyses of the bending experimental test, which are complementary to the experimental test results, to identify said parameter L* and h* and to determine the correct material viscosity as a function of the temperature, and wherein said methodology is characterized by the fact that; a. said bending experimental test is performed by using a C shaped test specimen that is assembled on a dedicated supporting structure, in order to avoid adhesion problems of the conventional bending test, and by installing the assembly of said test specimen and said supporting structure, on the measuring instrument, wherein said test specimen is not in contact with the supporting rods of the measuring instrument during the whole test, b. said supporting structure comprises a pair of boles, shaped to allow the installation on supporting rods of the measuring instrument, a pair of fins that allow the placement of the test specimen and a pair of fins with rounded edges that during the bending test are always in contact with the test specimen adapted to prevent any horizontal movement of the specimen. (i) producing a significant number of material specimens to be used for a bending experimental tests with an optical instrument; (ii) carrying out the bending experimental test in which the material specimen, loaded at least by its own weight, undergoes thermal and viscous deformations and measuring the vertical displacement in the specimen midpoint as a function of temperature; (iii) deriving, starting from said experimental test, a bending curve and a bending rate curve in the specimen midpoint; (iv) repeating the bending experimental test for a significant number of specimens in order to verify the results repeatability; (v) defining an equation to calculate the material viscosity by using the bending rate curve, δ ̇ x = 0 *: η = 5 ⁢ ρ g L * 4 32 ⁢ δ ̇ x = 0 * ⁢ h * 2 where g is the gravity acceleration, p the material densification curve, L* and h* are, respectively, the span and the section height of an equivalent beam that, in the two points bending configuration test, deforms with the same bending rate, δ ̇ x = 0 *, of the C shaped specimen, (vi) performing FEM numerical analyses of the bending experimental test, which are complementary to the experimental test results, to identify said parameter L* and h* and to determine the correct material viscosity as a function of the temperature, a. said bending experimental test is performed by using a C shaped test specimen that is assembled on a dedicated supporting structure, in order to avoid adhesion problems of the conventional bending test, and by installing the assembly of said test specimen and said supporting structure, on the measuring instrument, wherein said test specimen is not in contact with the supporting rods of the measuring instrument during the whole test, b. said supporting structure comprises a pair of boles, shaped to allow the installation on supporting rods of the measuring instrument, a pair of fins that allow the placement of the test specimen and a pair of fins with rounded edges that during the bending test are always in contact with the test specimen adapted to prevent any horizontal movement of the specimen.