4D characterisation of damage and fracture mechanisms of ultra high performance fibre reinforced concrete by in-situ micro X-Ray computed tomography tests. (February 2020)

• Record Type: Journal Article
• Authors: Yang, Z.J.; Qsymah, A.; Peng, Y.Z.; Margetts, L.; Sharma, R.
• Is Part Of: Cement & concrete composites. Volume 106(2020)
• Publication Date: 2020-02
• Subjects: Wedge split -- Ultra high performance fibre reinforced concrete -- Fracture mechanism -- Fibre orientation -- In-situ microscale X-ray computed tomography; Composite-reinforced concrete -- Periodicals; Concrete -- Periodicals; Composite materials -- Periodicals; Composites de ciment -- Périodiques; Béton -- Périodiques; Composites -- Périodiques; Béton léger -- Périodiques; Cement composites; Composite materials; Composite-reinforced concrete; Concrete; Lightweight concrete; Periodicals; Electronic journals; 620.135
• DOI: 10.1016/j.cemconcomp.2019.103473
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: In-situ microscale X-ray computed tomography (μXCT) tests of ultra high performance fibre reinforced concrete (UHPFRC) specimens were conducted under progressive wedge-split loading for the first time. A sequence of μXCT images of two 40 × 20 × 25 mm notched specimens were obtained at different loads with a voxel resolution of 16.9 μm. Through 3D image processing, the UHPFRC's internal microstructures are characterised and the complicated damage and fracture mechanisms are visualised, including bridging, bending and pull-out of fibres, spalling and fracture of matrix, and evolution of micro-cracks into macro-cracks. The deformed μXCT images clearly show the significant effects of steel fibres: suppressing microcracks from propagation, leading to dispersed multiple cracks, and contributing to deviate the originally vertical crack towards the overall fibre orientation across the cracks. It is concluded the in-situ μXCT tests provide an unrivalled tool for elucidation of complicated damage and fracture evolution in UHPFRC with high-resolution 3D images that will be invaluable for validation of numerical models and optimisation of the material's micro-structures.