For important structures ascertain the concrete strength required by the design is not always easy. In fact, for the amount of concrete castings carried out during the construction phases, there are many factors that affect the strength value. This factors are related to the material properties (w / c ratio, quality and types of aggregates, ...) and they are also related to the measurement mode on the cubic specimens taken from the concrete castings (packaging, curing, compressive tests, ...). When the construction works are over, these reasons lead often to carried out destructive and non-destructive tests which allow to compare the design strength with the in-situ value. If used in conjunction with simple numerical procedures (proposal in literature) the experimental tests allow to determine the influence of the compaction degree of material on the concrete strength. A compaction  poorly executed produces porosity in concrete that make the material more penetrable, less lasting and low strength.

This paper proposes the numerical processing of the strength obtained from cubic specimens made ​​during the concrete castings and from drilled cores extracted in-situ for the Esaro's dam (Cosenza). In addition to the statistical processing of the sample, for verifying consistency with the homogeneous classes provided in the project, with using an analytical methodology (proposal in the literature), the influence of compaction degree on in-situ strength value was evaluated qualitatively.