Experimental modal analysis for fast monitoring of earthen samples drying-induced stiffness changes

This paper presents the investigation for the development of a characterization method for rammed earth samples. This method is based on modal analysis of the frequency spectral response of samples to an excitation by impulse shock method. This allows for the estimation of elastic parameters, particularly the Young’s modulus of materials in a non-destructive manner, by identifying the specimens’ resonance frequencies. The preparation of specimens, the development of the test protocol, and the pre-processing of modal analysis methods are briefly presented. The development of this method enabled the implementation of a consecutive measurement campaign on the same samples, allowing us to monitor the evolution of their Young’s modulus during the drying phase. The primary results of these tests are presented, along with a preliminary positive conclusion regarding the repeatability of the non-destructive characterization method.