Advances in Computed Tomography for Geomaterials: GeoX 2010

Evaluation of Porosity in Geomaterials Treated with Biogrout Considering Partial Volume Effect

Y. Kobayashi¹ — S. Kawasaki¹ — M. Kato¹ — T. Mukunoki² — K. Kaneko¹

¹Hokkaido UniversityKita 13 Nishi 8, Kita-ku, Sapporo [e-mail]

 

² Kumamoto University2-39-1, Kurokami, Kumamoto [e-mail]

ABSTRACT. This study evaluates the change in porosity of a biogrout specimen using micro-focus x-ray CT scanner and image processing. First, we selected the suitable geomaterials for evaluation of porosity. The results showed that glass beads whose particle size was 0.50-0.71mm were suitable. Second, we calculated the porosity of the glass beads using a method for evaluation of porosity based on a maximum likelihood thresholding method considering the effect of mixels, which are pixels having a two-phase structure. The result showed that the ratio of the porosity of grouted geomaterial to that of ungrouted one was 0.98-0.99, whereas the value estimated by the measurement of changes in concentration of calcium ion was 0.98. Thus, both values closely agreed. Therefore, this study clarifies that the method enables us to evaluate small changes in porosity with great accuracy.

 

KEYWORDS: porosity, threshold, mixel, biogrout, micro-focus x-ray CT

1. Introduction

Grouting is a technology to inject cementitious and non-cementitious materials ...