A method for examining a solidifying and/or hardening material such as cement, concrete, or the like, using ultrasound waves emitted by an ultrasound transmitter, wherein the ultrasonic waves penetrate the solidifying and/or hardening material and are continuously measured and analyzed, the method comprising the following method steps:
- i) recording the signal shapes of the ultrasound waves penetrating the material during solidification and/or hardening of the material;
- ii) extracting from the ultrasound wave shapes during the entire course of solidification and/or hardening of the material at least one property selected from the group consisting of:
- a. the change with time of the compression wave velocity,
- b. the relative energy of the ultrasound waves, and
- c. the frequency spectra of the ultrasound waves;
- iii) approximating the property of step ii) by a compensating function having free parameters;
- iv) associating the free parameters of the compensation function with the properties of the material;
- and
- v) determining the material properties of the material by comparison of a current measurement with reference values of these parameters using the free parameters of the compensation function.