Studies on the spatial variability of rebound hammer test results recorded at in-situ testing

Variability of the in-situ rebound hammer tests is composed of the inherent variability of the measuring method and the spatial variability of the concrete performance properties.In-situ, Schmidt rebound hammer tests were performed at the bottom surface of a concrete slab, with dimensions of 25.0 m × 7.5 m.The studied region on was 22.0 m × 6.0 m.The analysis of the inherent variability of the rebound hammer tests was limited to the comparison of the statistical location parameters; mean, median and mode values.The spatial variability was analysed by contour plots and semivariograms of the statistical location parameters.It was demonstrated that the geostatistical methods may be applicable for the much smaller scale concrete structures than the scale of geological formations.Semivariograms and semivariogram models seem to be useful tools for the characterisation of spatial variability of concrete structures.