Open Access

ARTICLE

Utilization of Dredged River Sediment in Preparing Autoclaved Aerated Concrete Blocks

Kai Zhang^1,2, Qunshan Wei^1,2,*, Shuai Jiang³, Zhemin Shen⁴, Yanxia Zhang^1,2, Rui Tang^1,2, Aiwu Yang^1,2, Christopher W. K. Chow⁵
1 College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China
2 State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai, 201620, China
3 National Engineering Research Center of Dredging Technology and Equipment, Shanghai, 200120, China
4 School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
5 Scarce Resources and Circular Economy (ScaRCE), UniSA STEM, University of South Australia, Mawson Lakes, SA 5095, Australia
* Corresponding Author: Qunshan Wei. Email:
(This article belongs to this Special Issue: Recycled Concrete Towards a Sustainable Society)

Journal of Renewable Materials 2022, 10(11), 2989-3008. https://doi.org/10.32604/jrm.2022.019821

Received 17 October 2021; Accepted 17 January 2022; Issue published 29 June 2022

Abstract

In this study, the dredged river sediment, soft texture and fine particles, is mixed with other materials and transformed into eco-friendly autoclaved aerated concrete (hereinafter referred to as AAC) blocks. The results indicated the bricks produced under the conditions of 30%–34% dredged river sediment, 24% cement, 10% quick lime, 30% fly ash, 2% gypsum and 0.09% aluminum powder with 0.5 water to material ratio, 2.2 MPa autoclave pressure and 6 h autoclave time, the average compressive strength of 4.5 MPa and average dry density of 716.56 kg/m³ were obtained, the two parameters (strength & density) both met the requirement of national industry standard. At the same time, the contents of dredged river sediment, cement, lime, fly ash, gypsum and aluminum powder were 15%, 48%, 20%, 15%, 2% and 0.09%, respectively, and the non-AAC block made of 0.5 water to material ratio, the average compressive strength of 3.1 MPa and average dry density of 924.19 kg/m³ were obtained, the two parameters (strength & density) also met the requirement of national industry standard. In addition, the AAC block’s phase composition and morphology were micro-analyzed by SEM and XRD, the main substances in AAC block were found to be tobermorite and CSH, Among them, the chemical bond between Si-O-Si and Al-O-Al is broken, Al-O-Si is regenerated, Al substituted tobermorite with better strength is formed, and the compressive strength of AAC is further improved.

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Keywords

Autoclaved aerated concrete; dredged river sediment; compressive strength; frost-resistance; moisture content; microstructure

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