title: A binary concrete crack self-healing system containing oxygen-releasing tablet and bacteria and its Ca2+-precipitation performance.
abstract: A strategy to supply molecular oxygen for microbial calcium precipitation was developed for the first time. Firstly, a controlled oxygen-releasing tablet (ORT) containing CaO2and lactic acid with a suitable ratio of 9:1 was developed. It can provide a stable oxygen supply and maintain pH in the range of 9.5-11.0 for 45 days while contacting with water. In the presence of oxygen, a self-healing bacterium H4 spores germinated more effectively and maintained high metabolic activity. Furthermore, H4 vegetative cells induced 50 % more calcium precipitation than that obtained without oxygen supply. Finally, a binary self-healing system containing bacterial spores and ORT was established. The calcium precipitation experiments showed that H4 in the binary self-healing system precipitated 27.5 mM calcium with oxygen supply after 32 days and dissolved oxygen (DO) concentration of the solution decreased from 15 to 4 mg l-1, while only 6.9 mM calcium precipitation was obtained without oxygen supply. This work can disclose the effect of oxygen on microbial calcium precipitation and further lay a foundation for the establishment of ternary self-healing system containing bacteria, ORT, and nutrients, which will be promising for the self-healing of cracks deep inside the concrete structure.
authors.affiliation: College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060, China.|Guangdong Province Key Laboratory of Durability for Marine Civil Engineering, The Key Laboratory on Durability of Civil Engineering in Shenzhen, School of Civil Engineering, Shenzhen University, Shenzhen, 518060, China.
authors.forename: J L
authors.initials: JL
authors.lastname: Zhang
authors.affiliation: College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060, China.
authors.forename: C G
authors.initials: CG
authors.lastname: Wang
authors.affiliation: College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060, China.
authors.forename: Q L
authors.initials: QL
authors.lastname: Wang
authors.affiliation: College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060, China.
authors.forename: J L
authors.initials: JL
authors.lastname: Feng
authors.affiliation: College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060, China.
authors.forename: W
authors.initials: W
authors.lastname: Pan
authors.affiliation: College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060, China.
authors.forename: X C
authors.initials: XC
authors.lastname: Zheng
authors.affiliation: Guangdong Province Key Laboratory of Durability for Marine Civil Engineering, The Key Laboratory on Durability of Civil Engineering in Shenzhen, School of Civil Engineering, Shenzhen University, Shenzhen, 518060, China.
authors.forename: B
authors.initials: B
authors.lastname: Liu
authors.affiliation: Guangdong Province Key Laboratory of Durability for Marine Civil Engineering, The Key Laboratory on Durability of Civil Engineering in Shenzhen, School of Civil Engineering, Shenzhen University, Shenzhen, 518060, China.
authors.forename: N X
authors.initials: NX
authors.lastname: Han
authors.affiliation: Guangdong Province Key Laboratory of Durability for Marine Civil Engineering, The Key Laboratory on Durability of Civil Engineering in Shenzhen, School of Civil Engineering, Shenzhen University, Shenzhen, 518060, China. xingf@szu.edu.cn.
authors.forename: F
authors.initials: F
authors.lastname: Xing
authors.affiliation: College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060, China. dengxu@szu.edu.cn.
authors.forename: X
authors.initials: X
authors.lastname: Deng
mesh_terms: D001407:Bacillus / Q000254:growth & development / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D011232:Chemical Precipitation; D003252:Construction Materials / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D013171:Spores, Bacterial / Q000254:growth & development / Q000378:metabolism*; D013607:Tablets / Q000378:metabolism*
chemical_list: D013607:Tablets; D019344:Lactic Acid; D010100:Oxygen; D002118:Calcium
keywords: Bacillus sp.; Concrete crack; Microbial calcium precipitation; Oxygen supply; Self healing