3D quantification for aggregate morphology using surface discretization based on solid modeling

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Sphericity, form dimensions, and angularity are important morphological properties of aggregates that significantly affect the microstructure of grain-based materials and their macromechanical performance. The objective of this paper was to quantify aggregate morphology, including sphericity index (SI), dimension index (DI), and angularity index (AI) based on three-dimensional (3D) solid modeling. The methodology consisted of three main steps, as follows: (1) the 3D solid model of each aggregate was developed from X-ray computed tomography (CT) imaging; (2) the model surface was discretized into triangle facets, and the vertexes of facets were used to accurately retrieve the minimum bounding sphere (MBS) and the minimum bounding box (MBB) of the aggregate model for SI and DI calculation, respectively; and (3) consequently, the facets were well clustered to represent aggregate angles for their magnitude measurements, which were used to quantify the AI. The 3D SI, DI, and AI of 11 grains were measured virtually with the proposed approach, which indicates the benefits of the 3D method in the accurate quantification of aggregate sphericity, form dimensions, and angularity.

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©2019 American Society of Civil Engineers. Publisher's version of record: https://doi.org/10.1061/(ASCE)MT.1943-5533.0002766

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Journal of Materials in Civil Engineering