Sulphate reduction in waste concrete aggregate Using bacillus subtilis

Waste concrete aggregate (WCA) can be re-utilised as a recycled material as it applies to numerous functions. High sulphate content in attached cement mortar was identified as a weakness of recycled material due to the developed expansion of delayed ettringite formation (DEF). The DEF results in mi...

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Main Authors: Abdul aziz, Nurhanim, Mohamed jamil, Putri anis syahira, Yusoff, Mohd zarir, Ismail, Norli
Format: Article
Language:en
Published: Umt 2024
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Online Access:http://eprints.uthm.edu.my/12522/1/J18008_30a19351393b580a45e37b78f6c26c6d.pdf
http://eprints.uthm.edu.my/12522/
http://doi.org/10.46754/jssm.2024.04.002
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_version_ 1833419811524182016
author Abdul aziz, Nurhanim
Mohamed jamil, Putri anis syahira
Yusoff, Mohd zarir
Ismail, Norli
author_facet Abdul aziz, Nurhanim
Mohamed jamil, Putri anis syahira
Yusoff, Mohd zarir
Ismail, Norli
author_sort Abdul aziz, Nurhanim
building UTHM Library
collection Institutional Repository
content_provider Universiti Tun Hussein Onn Malaysia
content_source UTHM Institutional Repository
continent Asia
country Malaysia
description Waste concrete aggregate (WCA) can be re-utilised as a recycled material as it applies to numerous functions. High sulphate content in attached cement mortar was identified as a weakness of recycled material due to the developed expansion of delayed ettringite formation (DEF). The DEF results in micro-crack formation, which affects the compressive strength. The main objective of the present study was to treat WCA by Bacillus subtilis before being reused in recycled concrete mortar (RCM) production. The DEF of WCA was identified using X-ray diffractometric (XRD) techniques and soluble sulphate tests. The efficiency of B. subtilis in treating WCA was evaluated based on sulphate reduction on three variable factors, i.e., B. subtilis concentration, B. subtilis: WCA ratio, 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 RC was subsequently evaluated to determine its durability. Results revealed that WCA was rich in ettringite and contained 0.53% sulphate. The sulphate content in WCA was successfully reduced to 81.5% by B. subtilis when B. subtilis concentration was at 0.2 x 108 CFU mL1 , the B. subtilis: WCA ratio was 1:1 and the retention time was increased up to the 4th day. The construction of RCM using TWCA can potentially replace the natural concrete aggregate due to its higher compressive strength (26 MPa) compared to control (20 MPa). The study indicated that B. subtilis efficiently reduced sulphate in WCA to avoid microcrack formation on the RC surface.
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spelling my.uthm.eprints-125222025-05-05T06:43:10Z http://eprints.uthm.edu.my/12522/ Sulphate reduction in waste concrete aggregate Using bacillus subtilis Abdul aziz, Nurhanim Mohamed jamil, Putri anis syahira Yusoff, Mohd zarir Ismail, Norli TA Engineering (General). Civil engineering (General) Waste concrete aggregate (WCA) can be re-utilised as a recycled material as it applies to numerous functions. High sulphate content in attached cement mortar was identified as a weakness of recycled material due to the developed expansion of delayed ettringite formation (DEF). The DEF results in micro-crack formation, which affects the compressive strength. The main objective of the present study was to treat WCA by Bacillus subtilis before being reused in recycled concrete mortar (RCM) production. The DEF of WCA was identified using X-ray diffractometric (XRD) techniques and soluble sulphate tests. The efficiency of B. subtilis in treating WCA was evaluated based on sulphate reduction on three variable factors, i.e., B. subtilis concentration, B. subtilis: WCA ratio, 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 RC was subsequently evaluated to determine its durability. Results revealed that WCA was rich in ettringite and contained 0.53% sulphate. The sulphate content in WCA was successfully reduced to 81.5% by B. subtilis when B. subtilis concentration was at 0.2 x 108 CFU mL1 , the B. subtilis: WCA ratio was 1:1 and the retention time was increased up to the 4th day. The construction of RCM using TWCA can potentially replace the natural concrete aggregate due to its higher compressive strength (26 MPa) compared to control (20 MPa). The study indicated that B. subtilis efficiently reduced sulphate in WCA to avoid microcrack formation on the RC surface. Umt 2024 Article PeerReviewed text en http://eprints.uthm.edu.my/12522/1/J18008_30a19351393b580a45e37b78f6c26c6d.pdf Abdul aziz, Nurhanim and Mohamed jamil, Putri anis syahira and Yusoff, Mohd zarir and Ismail, Norli (2024) Sulphate reduction in waste concrete aggregate Using bacillus subtilis. Journal of Sustainability Science and Management, 19 (4). pp. 10-27. ISSN 2672-7226 http://doi.org/10.46754/jssm.2024.04.002
spellingShingle TA Engineering (General). Civil engineering (General)
Abdul aziz, Nurhanim
Mohamed jamil, Putri anis syahira
Yusoff, Mohd zarir
Ismail, Norli
Sulphate reduction in waste concrete aggregate Using bacillus subtilis
title Sulphate reduction in waste concrete aggregate Using bacillus subtilis
title_full Sulphate reduction in waste concrete aggregate Using bacillus subtilis
title_fullStr Sulphate reduction in waste concrete aggregate Using bacillus subtilis
title_full_unstemmed Sulphate reduction in waste concrete aggregate Using bacillus subtilis
title_short Sulphate reduction in waste concrete aggregate Using bacillus subtilis
title_sort sulphate reduction in waste concrete aggregate using bacillus subtilis
topic TA Engineering (General). Civil engineering (General)
url http://eprints.uthm.edu.my/12522/1/J18008_30a19351393b580a45e37b78f6c26c6d.pdf
http://eprints.uthm.edu.my/12522/
http://doi.org/10.46754/jssm.2024.04.002
url_provider http://eprints.uthm.edu.my/