The four point bending flexural test provides values for the modulus of elasticity in bending E_f, flexural stress sigma_f, flexural strain varepsilon_f and the flexural stress-strain response of the material. This test is very similar to the three point bending flexural test. The major difference being that the addition of a 4th bearing brings a much larger portion of the beam to the maximum stress, as opposed to only the material right under the central bearing.This difference is of prime importance when studying brittle materials, where the number and severity of flaws exposed to the maximum stress is directly related to the flexural strength and crack initiation.It is one of the most widely used apparatus to characterize fatigue and flexural stiffness of asphalt mixtures [1]
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