Statistical analysis of the critical percolation of ITZ around polygonal aggregates in three-phase concrete materials

A Numerical Study of ITZ Percolation in Polyphase Concrete Systems Considering the Synergetic Effect of Aggregate Shape- and Size-Diversities

“…For instance, by assuming the aggregate particles as regular-shaped particles (e.g., spheres [ 13 , 14 , 15 ], ellipsoids [ 16 , 17 ], polygons [ 18 ], polyhedrons [ 19 ], etc.) with polydisperse sizes, the sensitivity of the ITZ percolation to the aggregate shapes and sizes was studied individually, and the findings were concluded as below: (a) the ITZ thickness is the dominant factor that determines the ITZ percolation [ 14 , 15 , 16 , 17 , 18 , 19 ]; (b) the percolation threshold of ITZ is very sensitive to the specific surface areas (SSA) of particles and shows an obviously downward trend with the increase of SSA [ 17 , 18 , 19 ]; (c) with the increase of the aspect ratio of elongated ellipsoids [ 16 , 17 ] or the decrease of the number of polygon edges [ 18 ] and polyhedron faces [ 19 ], the percolation threshold of ITZ around them could be decreased significantly. All of these studies [ 14 , 15 , 16 , 17 , 18 , 19 ] supported the importance of aggregate shape and size in the prediction of ITZ percolation.…”

“…with polydisperse sizes, the sensitivity of the ITZ percolation to the aggregate shapes and sizes was studied individually, and the findings were concluded as below: (a) the ITZ thickness is the dominant factor that determines the ITZ percolation [ 14 , 15 , 16 , 17 , 18 , 19 ]; (b) the percolation threshold of ITZ is very sensitive to the specific surface areas (SSA) of particles and shows an obviously downward trend with the increase of SSA [ 17 , 18 , 19 ]; (c) with the increase of the aspect ratio of elongated ellipsoids [ 16 , 17 ] or the decrease of the number of polygon edges [ 18 ] and polyhedron faces [ 19 ], the percolation threshold of ITZ around them could be decreased significantly. All of these studies [ 14 , 15 , 16 , 17 , 18 , 19 ] supported the importance of aggregate shape and size in the prediction of ITZ percolation. However, there are still several problems that need to be improved because of two simplistic assumptions generally used in the previous papers.…”

“…However, there are still several problems that need to be improved because of two simplistic assumptions generally used in the previous papers. The first assumption is that both coarse aggregates and fine aggregates are commonly simplified as regular particles of uniform shape, which overlooks the geometric differences between them [ 15 , 16 , 18 , 19 ]. As shown in Figure 1 , the aggregate particles in concrete can be roughly classified into two categories: coarse aggregates (i.e., gravels) and fine aggregates (i.e., sands).…”

“…As shown in Figure 1 , the aggregate particles in concrete can be roughly classified into two categories: coarse aggregates (i.e., gravels) and fine aggregates (i.e., sands). Morphologically, the geometric shapes of coarse aggregates are very similar to the regular/irregular convex polygons or polyhedrons [ 18 , 19 , 20 , 21 , 22 , 23 ]. By contrast, the fine aggregates look more like the non-spherical particles of smooth surfaces such as spheres [ 13 , 14 , 15 ], ellipsoids [ 16 , 17 ], and ovoids [ 7 , 24 , 25 ], etc.…”

Investigation on Pore Structure and Permeability of Concrete–Rock Interfacial Transition Zones Based on Fractal Theory

“…It is believed that the addition of colloids can fill the accumulation pores of cement particles and reduce the content of calcium hydroxide (CH), increasing the ITZ compactness. The influences of aggregates (including light aggregates, heavy aggregates, different particle sizes and shapes) on the ITZ microstructural characteristics were discussed by Lin [12], Bentz et al [13], and Lyu et al [14], respectively. The results indicate that the ITZ between the light porous aggregate and cement slurry generates a denser ITZ microstructure.…”