Microbial induced calcite precipitation treatment on tropical residual soil

Biomediated soil improvement, also known as Microbial Induced Calcite Precipitation (MICP), is a promising new branch of microbial geotechnology. Earlier MICP studies only focused on sandy soils, but more recent studies have also investigated the potential and feasibility of MICP on tropical residua...

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Main Author:	Tiong, Kenny Ping Chiet
Format:	Thesis
Language:	English
Published:	2016
Subjects:	TA Engineering (General) Civil engineering (General)
Online Access:	http://eprints.utm.my/id/eprint/78739/1/KennyTiongPingPFKA2016.pdf
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spelling	my-utm-ep.787392018-08-30T08:06:49Z Microbial induced calcite precipitation treatment on tropical residual soil 2016-07 Tiong, Kenny Ping Chiet TA Engineering (General). Civil engineering (General) Biomediated soil improvement, also known as Microbial Induced Calcite Precipitation (MICP), is a promising new branch of microbial geotechnology. Earlier MICP studies only focused on sandy soils, but more recent studies have also investigated the potential and feasibility of MICP on tropical residual soil. The main objective of this study is to examine the feasibility of MICP and the mechanisms involved between two types of bacteria and chemical reagents in improving the strength of tropical residual soil. Essentially, this was about identifying the optimized treatment conditions as well as the effects of some specific MICP parameters and curing on unconfined compressive strength (UCS) development and calcite distribution. Two bacteria from the Bacillus family, namely, Bacillus subtilis and Sporosarcina pasteurii, were used as urease producing bacteria. The tropical residual silt soil with 80% fine soil was compressed to a cylindrical sample measuring 100 mm in height and 50 mm in diameter as well as having a dry density of 1.31 Mg/m3. Continuous injection method was employed. Series of tests were carried out, with each having different chemical reagents concentrations (0.15, 0.25, 0.35 or 0.45 M), reagent flow pressures (0.1, 0.2, 0.3 or 0.4 bars), and treatment durations (24, 48, 72 or 96 hours). Strength improvement of about 56.70% and 38.14% was immediately discovered after MICP treatment using Sporosarcina pasteurii and Bacillus subtilis, respectively. Additionally, strength improvement of about 30 to 104.12% were recorded after curing the samples for 3, 7, 14, 20, and 28 days. The optimum curing period was 14 days. The optimum treatment condition of MICP treatment for both bacteria consisted of 0.25 M of reagent concentration, 0.2 bars of reagent flow pressure, and 48 hours of treatment duration. The reagent flow pressure was the only MICP parameter that affected calcite distribution. No clear correlation was observed between calcite precipitation and strength. The two bacteria had distinctive responses to the designated treatment conditions as the behaviour of living microorganisms could differ although they are from the same family. This information were analysed to establish design charts for MICP practitioner in selecting optimal MICP parameters under different circumstances. 2016-07 Thesis http://eprints.utm.my/id/eprint/78739/ http://eprints.utm.my/id/eprint/78739/1/KennyTiongPingPFKA2016.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:106303 phd doctoral Universiti Teknologi Malaysia, Faculty of Civil Engineering Faculty of Civil Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TA Engineering (General) Civil engineering (General)
spellingShingle	TA Engineering (General) Civil engineering (General) Tiong, Kenny Ping Chiet Microbial induced calcite precipitation treatment on tropical residual soil
description	Biomediated soil improvement, also known as Microbial Induced Calcite Precipitation (MICP), is a promising new branch of microbial geotechnology. Earlier MICP studies only focused on sandy soils, but more recent studies have also investigated the potential and feasibility of MICP on tropical residual soil. The main objective of this study is to examine the feasibility of MICP and the mechanisms involved between two types of bacteria and chemical reagents in improving the strength of tropical residual soil. Essentially, this was about identifying the optimized treatment conditions as well as the effects of some specific MICP parameters and curing on unconfined compressive strength (UCS) development and calcite distribution. Two bacteria from the Bacillus family, namely, Bacillus subtilis and Sporosarcina pasteurii, were used as urease producing bacteria. The tropical residual silt soil with 80% fine soil was compressed to a cylindrical sample measuring 100 mm in height and 50 mm in diameter as well as having a dry density of 1.31 Mg/m3. Continuous injection method was employed. Series of tests were carried out, with each having different chemical reagents concentrations (0.15, 0.25, 0.35 or 0.45 M), reagent flow pressures (0.1, 0.2, 0.3 or 0.4 bars), and treatment durations (24, 48, 72 or 96 hours). Strength improvement of about 56.70% and 38.14% was immediately discovered after MICP treatment using Sporosarcina pasteurii and Bacillus subtilis, respectively. Additionally, strength improvement of about 30 to 104.12% were recorded after curing the samples for 3, 7, 14, 20, and 28 days. The optimum curing period was 14 days. The optimum treatment condition of MICP treatment for both bacteria consisted of 0.25 M of reagent concentration, 0.2 bars of reagent flow pressure, and 48 hours of treatment duration. The reagent flow pressure was the only MICP parameter that affected calcite distribution. No clear correlation was observed between calcite precipitation and strength. The two bacteria had distinctive responses to the designated treatment conditions as the behaviour of living microorganisms could differ although they are from the same family. This information were analysed to establish design charts for MICP practitioner in selecting optimal MICP parameters under different circumstances.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Tiong, Kenny Ping Chiet
author_facet	Tiong, Kenny Ping Chiet
author_sort	Tiong, Kenny Ping Chiet
title	Microbial induced calcite precipitation treatment on tropical residual soil
title_short	Microbial induced calcite precipitation treatment on tropical residual soil
title_full	Microbial induced calcite precipitation treatment on tropical residual soil
title_fullStr	Microbial induced calcite precipitation treatment on tropical residual soil
title_full_unstemmed	Microbial induced calcite precipitation treatment on tropical residual soil
title_sort	microbial induced calcite precipitation treatment on tropical residual soil
granting_institution	Universiti Teknologi Malaysia, Faculty of Civil Engineering
granting_department	Faculty of Civil Engineering
publishDate	2016
url	http://eprints.utm.my/id/eprint/78739/1/KennyTiongPingPFKA2016.pdf
_version_	1747818059435868160

Microbial induced calcite precipitation treatment on tropical residual soil

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