Porosimetry by Double-Random Multiple Tree Structuring in Virtual Concrete

Abstract

Two different porosimetry methods are presented in two successive papers. Inspiration for the development came from the rapidly-exploring random tree (RRT) approach used in robotics. The novel methods are applied to virtual cementitious materials produced by a modern concurrent algorithm-based discrete element modeling system, HADES. This would render possible realistically simulating all aspects of particulate matter that influence structure-sensitive features of the pore network structure in maturing concrete, namely size, shape and dispersion of aggregate and cement particles. Pore space is a complex tortuous entity. Practical methods conventionally applied for assessment of pore size distribution may fail or present biased information. Among them, mercury intrusion porosimetry and 2D quantitative image analysis are popular. The mathematical morphology operator "opening" can be applied to sections and even provide 3D information on pore size distribution, provided isotropy is guaranteed. Unfortunately, aggregate grain surfaces lead to pore anisotropy. The presented methods allow exploration of pore space in the virtual material, after which pore size distribution is derived from star volume measurements. In addition to size of pores their continuity is of crucial importance for durability estimation. Double-random multiple tree structuring (DRaMuTS), presented herein, and random node structuring (RaNoS) provide such information. The latter method will be introduced in a next issue of Image Anal Stereol.

Porosimetry by Random Node Structuring in Virtual Concrete

“…Particularly the latter have been demonstrated making the connections between pore trees of neighboring interfacial transition zones (ITZs), so that finite values of connected porosity were found for bulk paste. This was demonstrated by the earlier described DRaMuTS example in Stroeven et al (2012).…”

“…The two novel porosimetry methods introduced herein (RaNoS) and in Stroeven et al (2012) (DRaMuTS) are somewhat similar but still have different characteristics and potentialities. In RaNoS a system of UR dispersed nodes is first generated and then a clustering process starts, ultimately resulting in groups of connected nodes.…”

“…The presented novel methods (see also Stroeven et al, 2012) allow making a distinction between continuous pores (trunks) stretching over the full dimensions of the cement pocket, isolated pores and deadend pores branching off the trunks. Particularly the latter have been demonstrated making the connections between pore trees of neighboring interfacial transition zones (ITZs), so that finite values of connected porosity were found for bulk paste.…”

“…The two porosimetry methods introduced in Stroeven et al (2012) and herein are therefore intended to be applied to virtual cement pockets between neighboring aggregate grains in concrete. They are produced in an analogue version by the dynamic concurrent algorithm-based physical DEM system HADES.…”

Methodology for Porosimetry in Virtual Cementitious Composites to Economically and Reliably Estimate Permeability

“…DRaMuTS, the third building block of the porosimetry methodology, stands for a Double Random Multiple Tree Structuring system for delineating the complete pore network and for topology assessment (Stroeven et al, 2012a). By this method, randomized data structures are built incrementally in two stages.…”