Micro X-ray computed tomography image-based two-scale homogenisation of ultra high performance fibre reinforced concrete

A two-scale analytical-numerical homogenisation approach is developed to predict effective elastic properties of ultra high performance fibre reinforced concrete considering distribution of pore sizes acquired from 3D micro X-ray computed tomography (μXCT) images of 24.8 μm resolution. In the first scale, the mortar, consisting of sand, cement paste and a large number of small pores (10–600 μm), is homogenised using analytical Mori-Tanaka method with constituents’ moduli from micro-indentation. In the second, μXCT images of a 20 mm cube are converted to mesoscale representative volume elements for finite element homogenisation, with fibres and a small number of large pores (⩾600 μm) in the homogenised mortar. The resultant elastic moduli are compared favourably with experimental data. This approach accounts for a large number of pores with a wide size range yet without excessive computational cost. Effects of fibre volume fraction and orientation are investigated, demonstrating the approach’s potential to optimise the material’s micro-structure for desired properties.

Publisher Statement: NOTICE: this is the author’s version of a work that was accepted for publication in Construction and Building Materials. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Construction and Building Materials, [130, (2017)] DOI: 10.1016/j.conbuildmat.2016.09.020

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