Chloride diffusion in alkali-activated fly ash/slag concretes: Role of slag content, water/binder ratio, alkali content and sand-aggregate ratio
Article
Article Title | Chloride diffusion in alkali-activated fly ash/slag concretes: Role of slag content, water/binder ratio, alkali content and sand-aggregate ratio |
---|---|
ERA Journal ID | 3470 |
Article Category | Article |
Authors | Zhang, Jingxiao (Author), Ma, Yuwei (Author), Zheng, Jiazheng (Author), Hu, Jie (Author), Fu, Jiyang (Author), Zhang, Zuhua (Author) and Wang, Hao (Author) |
Journal Title | Construction and Building Materials |
Journal Citation | 261, pp. 1-12 |
Article Number | 119940 |
Number of Pages | 12 |
Year | 2020 |
Publisher | Elsevier |
Place of Publication | Netherlands |
ISSN | 0950-0618 |
Digital Object Identifier (DOI) | https://doi.org/10.1016/j.conbuildmat.2020.119940 |
Web Address (URL) | https://www.sciencedirect.com/science/article/pii/S0950061820319450 |
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. |
Keywords | Alkali-activated concrete; Chloride diffusion coefficient; Early age properties; Natural chloride diffusion tests; Pore structure |
ANZSRC Field of Research 2020 | 401602. Composite and hybrid materials |
400505. Construction materials | |
Byline Affiliations | Centre for Future Materials |
Guangzhou University, China | |
South China University of Technology, China | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q6zxx/chloride-diffusion-in-alkali-activated-fly-ash-slag-concretes-role-of-slag-content-water-binder-ratio-alkali-content-and-sand-aggregate-ratio
185
total views3
total downloads1
views this month0
downloads this month