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ID 117737
Author
Putra, Heriansyah Ehime University|Universitas Jambi
Yasuhara, Hideaki Ehime University
Kinoshita, Naoki Ehime University
Keywords
EMCP technique
calcite
aragonite
gypsum
grouting technique
soil improvement
Content Type
Journal Article
Description
The effectiveness of magnesium as a substitute material in enzyme-mediated calcite precipitation was evaluated. Magnesium sulfate was added to the injecting solution composed of urea, urease, and calcium chloride. The effect of the substitution on the amount of precipitated materials was evaluated through precipitation tests. X-ray powder diffraction and scanning electron microscopy analyses were conducted to examine the mineralogical morphology of the precipitated minerals and to determine the effect of magnesium on the composition of the precipitated materials. In addition to calcite, aragonite and gypsum were formed as the precipitated materials. The effect of the presence of aragonite and gypsum, in addition to calcite, as a soil-improvement technique was evaluated through unconfined compressive strength tests. Soil specimens were prepared in polyvinyl chloride cylinders and treated with concentration-controlled solutions, which produced calcite, aragonite, and gypsum. The mineralogical analysis revealed that the low and high concentrations of magnesium sulfate effectively promoted the formation of aragonite and gypsum, respectively. The injecting solutions which produced aragonite and calcite brought about a significant improvement in soil strength. The presence of the precipitated materials, comprising 10% of the soil mass within a treated sand, generated a strength of 0.6 MPa.
Journal Title
Crystals
ISSN
20734352
Publisher
MDPI
Volume
7
Issue
2
Start Page
59
Published Date
2017-02-20
Rights
This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
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DOI (Published Version)
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language
eng
TextVersion
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departments
Science and Technology