Title
Influence of pore property and alkalinity on the bio-deposition treatment efficiency of recycled aggregates
Author
Wang, Jianyun (Xi’an Jiaotong University)
Zhang, Rui (Xi’an Jiaotong University)
Hou, Fuxing (Xi’an Jiaotong University)
Ye, G. (TU Delft Materials and Environment) 
Date
2024
Abstract
Microbial induced calcium carbonate precipitation (MICP) technology has been successfully used to enhance the properties of recycled concrete aggregates. However, the complex source and varied physical and chemical properties of recycled aggregates may have influence on the modification efficiency since microbes are often sensitive to the surroundings. In this study, two representative types of recycled aggregates, recycled concrete aggregates (RCA) and recycled brick aggregates (RBA), were subjected to two kinds of MICP treatments, basic MICP treatment and sodium alginate (SA) aided MICP treatment. The absorption and desorption of bacteria in/on aggregates during MICP treatments were quantified. The physical and chemical properties of aggregates after the bio-treatments were tested, and the influence of alkalinity and pore structure of aggregates under various MICP treatment methods on treatment efficiency were detailed investigated. Results indicated that, when the aggregates were subjected to the basic MICP treatment, the treatment efficiency was more remarkable in RBA, because of its high porosity and moderate pH (around 8–9), which facilitated the absorption of bacteria in/on aggregates and urease activity respectively. While under SA-aided MICP treatment, the influence of pore structure and alkalinity of aggregates on the treatment efficiency was not significant compared with that under the basic MICP treatment, especially the mass of CaCO3 on the aggregates. The biogenic CaCO3 generated by SA-aided MICP treatment not only plugged micropores, but also distributed all over the entire surface of the aggregates, resulting in a sufficient repair of microcracks. Meanwhile, the surface repair may reduce the influence of pore structure and pH of aggregates on the precipitation process, thereby reducing the impact of varied physical and chemical properties of aggregates on the treatment efficiency, which was conducive to the widely unified application of SA-aided MICP treatment in the modification of recycled aggregate based on construction solid waste.
Subject
Alkalinity
Microbial induced carbonate precipitation (MICP)
Pore structure
Recycled aggregates
Sodium alginate
To reference this document use:
http://resolver.tudelft.nl/uuid:14f5082b-79bd-4d83-9087-ddb5b9c81a55
DOI
https://doi.org/10.1016/j.jobe.2024.109381
Embargo date
2024-10-18
ISSN
2352-7102
Source
Journal of Building Engineering, 89
Bibliographical note
Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
Part of collection
Institutional Repository
Document type
journal article
Rights
© 2024 Jianyun Wang, Rui Zhang, Fuxing Hou, G. Ye