Pore Structural and Fractal Analysis of the Effects of MgO Reactivity and Dosage on Permeability and F–T Resistance of Concrete
Publication Date
2022-02-15Journal Title
Fractal and Fractional
ISSN
2504-3110
Publisher
MDPI AG
Volume
6
Issue
2
Language
en
Type
Article
This Version
VoR
Metadata
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Wang, L., Song, X., Yang, H., Wang, L., Tang, S., Wu, B., & Mao, W. (2022). Pore Structural and Fractal Analysis of the Effects of MgO Reactivity and Dosage on Permeability and F–T Resistance of Concrete. Fractal and Fractional, 6 (2) https://doi.org/10.3390/fractalfract6020113
Abstract
<jats:p>Currently, the MgO expansion agent is widely used to reduce the cracking risk of concrete. The influence of MgO reactivity (50 s and 300 s) and dosage (0, 4 wt.% and 8 wt.%, by weight of binder) on the air void, pore structure, permeability and freezing–thawing (F–T) resistance of concrete were studied. The results indicate (1) the addition of 4–8 wt.% reactive MgO (with reactivity of 50 s and termed as M50 thereafter) and weak reactive MgO (with reactivity of 300 s and termed M300 thereafter) lowers the concrete’s compressive strength by 4.4–17.2%, 3.9–16.4% and 1.9–14.6% at 3, 28 and 180 days, respectively. The increase in MgO dosage and reactivity tends to further reduce the concrete strength at all hydration ages. (2) Permeability of the concrete is closely related to the pore structure. M50 can densify the pore structure and lower the fraction of large capillary pores at an early age, thus it is beneficial for the impermeability of concrete. In contrast, M300 can enhance the 180-day impermeability of concrete since it can densify the pore structure only at a late age. (3) The influence of MgO on F–T resistance is minor since MgO could not change the air void parameters. (5) MgO concretes exhibit obvious fractal characteristics. The fractal dimension of the pore surface (Ds) exhibits a close relationship with the permeability property of concrete. However, no correlation can be found between F–T resistance and Ds.</jats:p>
Keywords
MgO, permeability, F–T resistance, pore, air void, fractal dimension
Sponsorship
Opening Funds of the Belt and Road Special Foundation of the State Key Laboratory of Hydrolo-gy-Water Resources and Hydraulic Engineering (2020492311, BSBE2020-2, 2020GBM07, 20JK0722)
Identifiers
External DOI: https://doi.org/10.3390/fractalfract6020113
This record's URL: https://www.repository.cam.ac.uk/handle/1810/334143
Rights
Licence:
https://creativecommons.org/licenses/by/4.0/
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