HOW TO GET RELIABLE 3D INFORMATION ON CONCRETE POROSITY?

摘要

Pores are an inherent constituent of concretes. Particularly the part of porosity that connects external surfaces of concrete elements is of research interest because harmful substances will be allowed traveling from one side to the other, or to the main reinforcement. Size distribution of pores (SDP) and the related critical pore size are generally considered important parameters. Further, of course, the process of pore de-percolation during hardening, and the de-percolation threshold could be considered relevant phenomena. Conventional methods for assessment of SDP like MIP, Wood's metal intrusion porosimetry, traditional 2D image analysis and 3D reconstruction of serially sectioned model concretes are evaluated against the method of subjecting single sections to the mathematical morphology "opening" operator. An alternative is application of star volume measurements in random points on pores displayed in single sections. These techniques are superior in economy (restricting labor intensity dramatically). Moreover, they yield reliable 3D information on the size distribution of pores.