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A platform for research: civil engineering, architecture and urbanism
Bacteria-induced internal carbonation of reactive magnesia cement
https://orcid.org/0000-0002-3923-0642
https://orcid.org/0000-0001-6066-8254
Highlights Bacteria is used to generate CO2 for strength gain of RMC through internal carbonation. Bacteria-induced internal carbonation promotes formation of HMCs in RMC paste. Flowability of bio-RMC paste increases by 20% while setting time remains unchanged. Urea can function as superplasticizer to reduce water demand of RMC paste.
Abstract With lower calcination temperature, reactive magnesia cement (RMC) can be a potential alternative to the Portland cement. However, RMC concrete requires accelerated carbonation curing from external sources which greatly hinder the wider applications of RMC. This study proposed a bacteria-based method for the strength gain of RMC through internal carbonation. Sporosarcina pasteurii, urea, and yeast extract were used as a carbonation agent for internal carbonation of RMC pastes. Results showed that the flowability of the fresh bio-RMC paste increased by 20% while the initial setting time remained unchanged. Besides serving as the CO2 provider, urea can also function as superplasticizer to reduce the water demand of the bio-RMC pastes. The resulting bio-RMC pastes showed a continuous strength gain with time, demonstrating the feasibility of bacteria-induced internal carbonation of RMC. Microstructure analysis revealed abundant formation of hydrated magnesium carbonates in the bio-RMC pastes, which is responsible for the strength gain of the bio-RMC pastes.
Bacteria-induced internal carbonation of reactive magnesia cement
https://orcid.org/0000-0002-3923-0642
https://orcid.org/0000-0001-6066-8254
Highlights Bacteria is used to generate CO2 for strength gain of RMC through internal carbonation. Bacteria-induced internal carbonation promotes formation of HMCs in RMC paste. Flowability of bio-RMC paste increases by 20% while setting time remains unchanged. Urea can function as superplasticizer to reduce water demand of RMC paste.
Abstract With lower calcination temperature, reactive magnesia cement (RMC) can be a potential alternative to the Portland cement. However, RMC concrete requires accelerated carbonation curing from external sources which greatly hinder the wider applications of RMC. This study proposed a bacteria-based method for the strength gain of RMC through internal carbonation. Sporosarcina pasteurii, urea, and yeast extract were used as a carbonation agent for internal carbonation of RMC pastes. Results showed that the flowability of the fresh bio-RMC paste increased by 20% while the initial setting time remained unchanged. Besides serving as the CO2 provider, urea can also function as superplasticizer to reduce the water demand of the bio-RMC pastes. The resulting bio-RMC pastes showed a continuous strength gain with time, demonstrating the feasibility of bacteria-induced internal carbonation of RMC. Microstructure analysis revealed abundant formation of hydrated magnesium carbonates in the bio-RMC pastes, which is responsible for the strength gain of the bio-RMC pastes.
Bacteria-induced internal carbonation of reactive magnesia cement
https://orcid.org/0000-0002-3923-0642
https://orcid.org/0000-0001-6066-8254
Highlights Bacteria is used to generate CO2 for strength gain of RMC through internal carbonation. Bacteria-induced internal carbonation promotes formation of HMCs in RMC paste. Flowability of bio-RMC paste increases by 20% while setting time remains unchanged. Urea can function as superplasticizer to reduce water demand of RMC paste.
Abstract With lower calcination temperature, reactive magnesia cement (RMC) can be a potential alternative to the Portland cement. However, RMC concrete requires accelerated carbonation curing from external sources which greatly hinder the wider applications of RMC. This study proposed a bacteria-based method for the strength gain of RMC through internal carbonation. Sporosarcina pasteurii, urea, and yeast extract were used as a carbonation agent for internal carbonation of RMC pastes. Results showed that the flowability of the fresh bio-RMC paste increased by 20% while the initial setting time remained unchanged. Besides serving as the CO2 provider, urea can also function as superplasticizer to reduce the water demand of the bio-RMC pastes. The resulting bio-RMC pastes showed a continuous strength gain with time, demonstrating the feasibility of bacteria-induced internal carbonation of RMC. Microstructure analysis revealed abundant formation of hydrated magnesium carbonates in the bio-RMC pastes, which is responsible for the strength gain of the bio-RMC pastes.
Bacteria-induced internal carbonation of reactive magnesia cement
Xiao, Xi (author) / Goh, Li Xuan (author) / Unluer, Cise (author) / Yang, En-Hua (author)
2020-11-16
Article (Journal)
Electronic Resource
English
MgO , Bacteria , Urea , Internal carbonation , Performance
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