Zhu, Binrong;
Pan, Jinlong;
Li, Junrui;
Wang, Penghui;
Zhang, Mingzhong;
(2022)
Relationship between microstructure and strain-hardening behaviour of 3D printed engineered cementitious composites.
Cement and Concrete Composites
, 133
, Article 104677. 10.1016/j.cemconcomp.2022.104677.
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Abstract
The tensile behaviour of engineered cementitious composites (ECC) is highly dependent on their microstructure characteristics. To date, the strain-hardening behaviour of printed ECC in relation to its microstructure is not yet fully understood. This study presents a systematic investigation on the macroscopic mechanical properties of normal and printed ECC with various polyethylene (PE) fibre lengths (6 and 12 mm) in relation to their microstructural features in terms of pore structure characteristics, fibre orientation and fibre dispersion through a series of mechanical tests and X-ray computed tomography (CT) and backscattered electron (BSE) image acquisition, processing and analysis. Results indicate that it is desirable to use block specimens for mould-casting fabrication as contrast to printed ECC samples. The printed ECC containing 1.5 vol% 6 mm and 0.5 vol% 12 mm PE fibres by extrusion-based 3D printing exhibits unique tensile ductility of over 5% and average crack width of less than 100 μm. Regarding pore structure, normal ECC has a higher probability of large pores (over 1 mm3) than printed ECC, which would increase the risk of damage localization and lead to a significant variation in tensile properties. Besides, normal ECC with thickness of 30 mm and printed ECC possess a similar fist cracking strength as indicated by similar pore size and fracture toughness. Compared to normal ECC, printed ECC has a more uniform dispersion of PE fibres, the orientation of which is more perpendicular to the loading direction, resulting in a higher average tensile strength and strain capacity than normal ECC.
| Type: | Article |
|---|---|
| Title: | Relationship between microstructure and strain-hardening behaviour of 3D printed engineered cementitious composites |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.cemconcomp.2022.104677 |
| Publisher version: | https://doi.org/10.1016/j.cemconcomp.2022.104677 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher's terms and conditions. |
| Keywords: | 3D concrete printing, Strain-hardening cementitious composites, Tensile properties, Microcracking, Fibre bridging effect, Pore structure |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Civil, Environ and Geomatic Eng UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10152118 |
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