Ultrasound evaluation of the mechanical properties as an investigation tool for the wood-polymer composites including olive wood flour

•description of the elaboration process of the bio-composite samples.•characterization of longitudinal and transverse velocities based on the spectral method.•identification of the Young's modulus and Poisson's coefficient at the studied frequency.•evaluation of the mechanical elastic properties according the ISO 527-1.•identification of the Hollomon's law characteristic parameters from the mechanical tests. This paper presents results obtained for the development of a wood-polymer composite (WPC) based on polypropylene (PP) reinforced by olive wood fibers (OWF). The effect of the wood flour content and its chemical fiber treatment (amino-silane) on the mechanical properties of the WPC was studied by ultrasonic methods and mechanical tensile test. The elastic properties of the studied PP/OWF compositions are discussed and both of the mentioned evaluations give similar tendencies even if the characterization methods are somewhat different. As a result, the increase of the fiber content and the addition of the amino-silane coupling agent is shown to improve the rigidity of composite materials. Eventually, a correlation factor between the estimated Young's moduli is established between the ultrasound values (for ε