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The role of bacterial urease activity on the uniformity of carbonate precipitation profiles of bio-treated coarse sand specimens.

Accepted version
Peer-reviewed

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Article

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Authors

Konstantinou, Charalampos  ORCID logo  https://orcid.org/0000-0002-4662-5327
Biscontin, Giovanna  ORCID logo  https://orcid.org/0000-0002-4662-5650
Soga, Kenichi 

Abstract

Protocols for microbially induced carbonate precipitation (MICP) have been extensively studied in the literature to optimise the process with regard to the amount of injected chemicals, the ratio of urea to calcium chloride, the method of injection and injection intervals, and the population of the bacteria, usually using fine- to medium-grained poorly graded sands. This study assesses the effect of varying urease activities, which have not been studied systematically, and population densities of the bacteria on the uniformity of cementation in very coarse sands (considered poor candidates for treatment). A procedure for producing bacteria with the desired urease activities was developed and qPCR tests were conducted to measure the counts of the RNA of the Ure-C genes. Sand biocementaton experiments followed, showing that slower rates of MICP reactions promote more effective and uniform cementation. Lowering urease activity, in particular, results in progressively more uniformly cemented samples and it is proven to be effective enough when its value is less than 10 mmol/L/h. The work presented highlights the importance of urease activity in controlling the quality and quantity of calcium carbonate cements.

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Keywords

4005 Civil Engineering, 31 Biological Sciences, 40 Engineering

Journal Title

Sci Rep

Conference Name

Journal ISSN

2045-2322
2045-2322

Volume Title

11

Publisher

Springer Science and Business Media LLC

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All rights reserved
Sponsorship
Engineering and Physical Sciences Research Council (EP/P013848/1)
BP International Centre for Advanced Materials (BP-ICAM)