Stereological Analysis of Aggregate Distribution in Contaminant Barrier Concrete

Abstract

The distribution of large aggregate particles in concrete is a significant determinant of concrete strength, durability and wave/fluid transmission characteristics. These characteristics are important with respect to the performance of concrete containment systems for interim storage of radioactive waste. Even distribution of aggregate particles within concrete matrix promotes spatial uniformity of concrete characteristics and minimizes the weakness that can develop in aggregate-deficient portions. The internal heterogeneity of concrete can be assessed destructively through standard load testing or indirectly through imaging and stereological analysis of obtained images. In this paper, an indexing methodology is developed and applied to the analysis of the areal and volumetric distribution of aggregates in samples extracted from hardened concrete grout for waste storage. Analyses of 301 mm mini-slices that were reconstructed into 4 full slices on the basis of a fixed aggregate diameter of 16.93 mm indicate a statistical goodness of fit χ2 value of 4, which is below the 5% significance level (18.3). This result indicates no significant unevenness in the spatial distribution of aggregate particles in the concrete grout. The results demonstrate that this stereologically based approach is useful in quality assurance assessments of emplaced concrete.