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Pore Structure Characteristics of Baking-Free Slag-Sludge Bricks and Its Correlations to Mechanical Properties

Lei Guo1,2,3,4, Pingping Chen1, Lixia Guo1,2,3,*, Zhilong Xue4, Zi Guan1, Mingru Li1
1 School of Water Conservancy, North China University of Water Resources and Electric Power, Zhengzhou, 450046, China
2 Henan Water Valley Research Institute, Zhengzhou, 450046, China
3 Henan Key Laboratory of Water Environment Simulation and Treatment, Zhengzhou, 450002, China
4 Henan Water Conservancy Investment YuYuan Water Ecology Co. Ltd., Pingyu, 463400, China
* Corresponding Author: Lixia Guo. Email:
(This article belongs to this Special Issue: Renewable building materials and properties)

Journal of Renewable Materials 2021, 9(10), 1805-1819.

Received 25 November 2020; Accepted 30 December 2020; Issue published 12 May 2021


In order to explore the relationship between the macroscopic properties and pore structure characteristics of baking-free slag-sludge bricks, the compressive strength and water absorption rate using aluminum industrial slag and sludge of different substitution rates were tested. Optical instruments and image analysis software were used to measure the parameters of the pore structure. Specifically, a fractal model was built based on the fractal theory, in which the fractal dimension was used as the characteristic index of the pore structure to analyze the correlation and interaction mechanism between the fractal dimension and the macroscopic mechanical properties. Based on this study, conclusions were drawn as follows: (1) The plane pore structure of baking-free bricks shows good fractal characteristics. With the increase of the aluminum industrial slag content, the fractal dimension becomes smaller and the pore structure develops well; with the increase of the sludge content, the fractal dimension becomes larger and the pore structure becomes worse; (2) As the fractal dimension of the plane pore structure increases, the compressive strength of baking-free bricks falls, and the porosity and water absorption rise; (3) The optimum content of baking-free slag-sludge bricks is aluminum industrial slag 30% and sludge 10%. After 7 days of curing, baking-free bricks boast higher performance, and fully meet the performance requirements of solid concrete bricks (MU40), which can reduce time costs, and enhance enterprise revenue.


Aluminum industrial slag; sludge; baking-free brick; mechanical property; fractal dimension

Cite This Article

Guo, L., Chen, P., Guo, L., Xue, Z., Guan, Z. et al. (2021). Pore Structure Characteristics of Baking-Free Slag-Sludge Bricks and Its Correlations to Mechanical Properties. Journal of Renewable Materials, 9(10), 1805–1819.

This work is licensed under a Creative Commons Attribution 4.0 International License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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