Removal Of Sulphate In Waste Recycle Aggregate Using Bacillus Subtilis

Waste concrete aggregate (WCA) is highly potential to be re-utilised as a recycled material as it is applicable to numerous functions. Attached cement paste on WCA surface has limited the potential WCA to be recycled as a part of raw construction materials. Low density, high in water absorption and...

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Main Author:	Aziz, Nurhanim Abdul
Format:	Thesis
Language:	English
Published:	2018
Subjects:	T Technology (General)
Online Access:	http://eprints.usm.my/48554/1/NURHANIM%20BINTI%20ABDUL%20AZIZ%20_hj.pdf
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id	my-usm-ep.48554
record_format	uketd_dc
spelling	my-usm-ep.485542021-03-08T07:29:55Z Removal Of Sulphate In Waste Recycle Aggregate Using Bacillus Subtilis 2018-07 Aziz, Nurhanim Abdul T Technology (General) Waste concrete aggregate (WCA) is highly potential to be re-utilised as a recycled material as it is applicable to numerous functions. Attached cement paste on WCA surface has limited the potential WCA to be recycled as a part of raw construction materials. Low density, high in water absorption and sulphate content are identified as the major contributing factors for this limitation. The sulphate content in delayed ettringite formation (DEF) from high water absorption of attached cement paste leads to DEF expansion and forms a micro-crack, causing a mass loss and affects the mechanical strength (compressive strength) of the concrete. The main objective of the present study was to treat WCA by incorporating the use of Bacillus subtilis before it was reused in recycled cement mortar (RCM) production. The characteristics of WCA were previously identified prior to the B. subtilis adhesion test. The efficiency of B. subtilis to treat WCA was evaluated based on four variable factors i.e. B. subtilis concentration, B. subtilis: WCA ratio, zeta potential, and retention time. Treated WCA (TWCA) from the WCA treatment by B. subtilis was reused as a part of RCM production. The compressive strength of RCM was subsequently evaluated to determine its quality. Results revealed that WCA had a low density, high water absorption, carbonated by attached cement paste and rich in ettringite. WCA contained 0.53 ±0.06 % of soluble sulphate and 47.76 ±8.43 % of attached cement paste. Leaching behaviour of inorganic element demonstrated Ca and SO42- as major elements, ranging from 10.06 mg L-1 to 149.15 mg L-1 and 30.78 mg L-1 to 38.90 mg L-1, respectively. 2018-07 Thesis http://eprints.usm.my/48554/ http://eprints.usm.my/48554/1/NURHANIM%20BINTI%20ABDUL%20AZIZ%20_hj.pdf application/pdf en public phd doctoral Universiti Sains Malaysia Pusat Pengajian Teknologi Industri
institution	Universiti Sains Malaysia
collection	USM Institutional Repository
language	English
topic	T Technology (General)
spellingShingle	T Technology (General) Aziz, Nurhanim Abdul Removal Of Sulphate In Waste Recycle Aggregate Using Bacillus Subtilis
description	Waste concrete aggregate (WCA) is highly potential to be re-utilised as a recycled material as it is applicable to numerous functions. Attached cement paste on WCA surface has limited the potential WCA to be recycled as a part of raw construction materials. Low density, high in water absorption and sulphate content are identified as the major contributing factors for this limitation. The sulphate content in delayed ettringite formation (DEF) from high water absorption of attached cement paste leads to DEF expansion and forms a micro-crack, causing a mass loss and affects the mechanical strength (compressive strength) of the concrete. The main objective of the present study was to treat WCA by incorporating the use of Bacillus subtilis before it was reused in recycled cement mortar (RCM) production. The characteristics of WCA were previously identified prior to the B. subtilis adhesion test. The efficiency of B. subtilis to treat WCA was evaluated based on four variable factors i.e. B. subtilis concentration, B. subtilis: WCA ratio, zeta potential, and retention time. Treated WCA (TWCA) from the WCA treatment by B. subtilis was reused as a part of RCM production. The compressive strength of RCM was subsequently evaluated to determine its quality. Results revealed that WCA had a low density, high water absorption, carbonated by attached cement paste and rich in ettringite. WCA contained 0.53 ±0.06 % of soluble sulphate and 47.76 ±8.43 % of attached cement paste. Leaching behaviour of inorganic element demonstrated Ca and SO42- as major elements, ranging from 10.06 mg L-1 to 149.15 mg L-1 and 30.78 mg L-1 to 38.90 mg L-1, respectively.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Aziz, Nurhanim Abdul
author_facet	Aziz, Nurhanim Abdul
author_sort	Aziz, Nurhanim Abdul
title	Removal Of Sulphate In Waste Recycle Aggregate Using Bacillus Subtilis
title_short	Removal Of Sulphate In Waste Recycle Aggregate Using Bacillus Subtilis
title_full	Removal Of Sulphate In Waste Recycle Aggregate Using Bacillus Subtilis
title_fullStr	Removal Of Sulphate In Waste Recycle Aggregate Using Bacillus Subtilis
title_full_unstemmed	Removal Of Sulphate In Waste Recycle Aggregate Using Bacillus Subtilis
title_sort	removal of sulphate in waste recycle aggregate using bacillus subtilis
granting_institution	Universiti Sains Malaysia
granting_department	Pusat Pengajian Teknologi Industri
publishDate	2018
url	http://eprints.usm.my/48554/1/NURHANIM%20BINTI%20ABDUL%20AZIZ%20_hj.pdf
_version_	1747821945997492224

Removal Of Sulphate In Waste Recycle Aggregate Using Bacillus Subtilis

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