Title: Distributions of Compressive Strength Obtained from Various Diameter Cores

Author(s): Ahmet Ozan Celik, Kadir Kilinc, Mustafa Tuncan, and Ahmet Tuncan

Publication: Materials Journal

Volume: 109

Issue: 6

Appears on pages(s): 597-606

Keywords: compressive strength; concrete cores; length-to-diameter ratio; probability density function; random variations; skewness.

DOI: 10.14359/51684157

Date: 11/1/2012

Abstract:
Test results from cores with diameters smaller than the standard sizes and with length-to-diameter (l/d) ratios less than 1 are considered to be unreliable due to higher variability in concrete strength. There is, however, still a lack of evidence in the literature regarding the unreliability of the compressive strength data for these lower-volume cores. Significantly important is the missing verification of such statements concerning the random variations of concrete strength, supported with statistical approaches. Statistically significant data sets under such conditions are very rare. In this study, the issue was addressed by exploring the features of the compressive strength obtained from different diameter cores using probabilistic concepts—in particular, when the l/d is less than 1— and shed light on the uncertainty regarding the reliability of the data taken under these conditions. The major outcome of this study is that concrete cores with diameters less than the standard-size cores and larger than microcores could be effectively used in practice to represent the variations in concrete strength, provided that the number of core samples and l/d are sufficiently high.