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The non destructive characterization of concrete structures implies developing new techniques in order to access different data on the material state. Ultrasonic wave's velocities are used to extract information, but the accessibility to the real structure is often difficult and their levels of sensitivity can be low. We propose two techniques that are not dependent on the wave path length measurement and presenting a good sensitivity to detect pathologies. They are based on ultrasonic propagation waves and have been recently developed and applied on laboratory tests and on site measurements. The first is the Backscattered Waves Analysis. The reflections of the ultrasonic waves by each aggregate on its path contribute to the signal construction. From this signal we deduce the waves attenuation. The second is the Non Linear Acousticity that consists in modulating a low frequency by a higher one. The parameter a characterizes the concrete's non linear behaviour. We present both techniques, and we compare their data as a function of the water saturation and damage of concretes.