Numerical study of the influence of W/C ratio and aggregate shape and size on the ITZ volume fraction in concrete

Naija, Ahmed; Miled, Karim

doi:10.1016/j.conbuildmat.2022.128950

Cited by 16 publications

(3 citation statements)

References 36 publications

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“…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.…”

Section: Introductionmentioning

confidence: 99%

“…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. In addition, the other simplistic assumption is that both the size distributions of coarse aggregates and fine aggregates in the literature about ITZ features are generally strung together and quantitatively represented by a single function [ 15 , 16 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ], which is also quite different from the reality in concrete. The oversimplification of aggregate shapes and size distributions in previous studies may result in a greater deviation between the predicted approximation and the reality.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the size gradations of them are also expressed by two separate functions instead of a single contiguous function as described in refs. [ 15 , 16 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. On the basis of above two preconditions, the sensitivity of ITZ percolation to the features of both coarse aggregates and fine aggregates in a more realistic way is studied in this paper.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2023

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The percolation of the interfacial transition zone (ITZ) is generally regarded as an important factor that may accelerate the penetration of aggressive agents in concrete materials, and its threshold is largely determined by the features of aggregates. In most numerical studies about ITZ percolation, both fine aggregates and coarse aggregates are assumed to be the particles of uniform shape, and their size distributions are generally strung together by a single function, which is quite different from reality. To quantify the ITZ percolation associated with the polydispersity of aggregate shapes and size gradations in a more realistic way, the two-dimensional (2D) meso-scale model of concrete is generated by simplifying coarse aggregates and fine aggregates as polygons and ovals, respectively. Moreover, the size gradations of them are also represented by two separate expressions. By combining these models with percolation theory, the percolation of ITZ in the 2D case is explicitly simulated, and the influence of aggregate shape- and size-diversities on the critical threshold ϕagg,c is studied in detail. Based on the simulated results of ϕagg,c, an empirically analytical expression is further proposed to fast predict the ITZ percolation, and its reliability is verified. The results show that the ITZ thickness, average aggregate fineness, coarse aggregate shape, and fine aggregate shapes are the four main contributing factors to the ITZ percolation. Compared with the existing literature, the proposed model here has a broader range of applications (e.g., mortar, concrete, and other granular systems) in the 2D case and can provide the larger predicted results, which may be closer to reality.

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