Zhang, Jingxiao and Ma, Yuwei and Zheng, Jiazheng and Hu, Jie and Fu, Jiyang and Zhang, Zuhua and Wang, Hao (2020) Chloride diffusion in alkali-activated fly ash/slag concretes: Role of slag content, water/binder ratio, alkali content and sand-aggregate ratio. Construction and Building Materials, 261:119940. pp. 1-12. ISSN 0950-0618
Abstract
The widespread application of alkali-activated fly ash/slag (AAFS) concrete requires the satisfaction of a series of performance criteria both from its early age properties (e.g. workability, strength) and long-term stability. In this study, long-term (till 180 days) natural chloride diffusion tests were conducted to evaluate the chloride diffusion in AAFS concretes prepared with different slag content, water/binder (w/b) ratio, alkali content, and sand-aggregate ratio. The results revealed that AAFS concretes obtained in this study were generally regarded as flow/high flow concretes (slump > 100 mm) with compressive strength > 50 MPa at 28 day. The free chloride diffusion coefficient (Df) of AAFS concretes was between 0.4 and 1.8 × 10-12 m2/s. The slag content and w/b were found as dominant parameters affecting the long-term chloride transport in AAFS concretes, while the sand-aggregate ratio presented a limited effect. The formation of more C-A-S-H gels (by increasing slag content ≥ 50%), and lower w/b (≤0.45) at Na2O content of ∼ 5% was preferred for AAFS concretes with good workability, strength and durability. MIP results indicated that capillary pores in AAFS reached percolation and became disconnected after 180 days. The long-term chloride diffusivity of AAFS concretes was closely related to the threshold pore diameter and volume of pores > 5 nm. The more larger pores, the higher chloride diffusion coefficient was.
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| Item Type: | Article (Commonwealth Reporting Category C) |
|---|---|
| Refereed: | Yes |
| Item Status: | Live Archive |
| Faculty/School / Institute/Centre: | Current - Institute for Advanced Engineering and Space Sciences - Centre for Future Materials (1 Jan 2017 -) |
| Faculty/School / Institute/Centre: | Current - Institute for Advanced Engineering and Space Sciences - Centre for Future Materials (1 Jan 2017 -) |
| Date Deposited: | 07 Mar 2022 03:15 |
| Last Modified: | 28 Mar 2022 04:09 |
| Uncontrolled Keywords: | Alkali-activated concrete; Chloride diffusion coefficient; Early age properties; Natural chloride diffusion tests; Pore structure |
| Fields of Research (2008): | 09 Engineering > 0905 Civil Engineering > 090503 Construction Materials 09 Engineering > 0912 Materials Engineering > 091202 Composite and Hybrid Materials |
| Fields of Research (2020): | 40 ENGINEERING > 4016 Materials engineering > 401602 Composite and hybrid materials 40 ENGINEERING > 4005 Civil engineering > 400505 Construction materials |
| Socio-Economic Objectives (2008): | E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering |
| Socio-Economic Objectives (2020): | 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280110 Expanding knowledge in engineering |
| Identification Number or DOI: | https://doi.org/10.1016/j.conbuildmat.2020.119940 |
| URI: | http://eprints.usq.edu.au/id/eprint/46465 |
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