KONG Li-juan,LIANG Zeng-yun,FANG Jun,WEI Wei,ZHANG Shi-wu,LI Yuan-yuan.Mutual Effect between the Biofilm and Concrete Protective Coatings in Sewage Environment[J],51(8):342-352 |
Mutual Effect between the Biofilm and Concrete Protective Coatings in Sewage Environment |
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DOI:10.16490/j.cnki.issn.1001-3660.2022.08.030 |
KeyWord:surface coating concrete sewage corrosion roughness biofilm growth |
Author | Institution |
KONG Li-juan |
State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures, Shijiazhuang Tiedao University, Shijiazhuang , China;School of Materials Science and Engineering, Shijiazhuang Tiedao University, Shijiazhuang , China |
LIANG Zeng-yun |
School of Materials Science and Engineering, Shijiazhuang Tiedao University, Shijiazhuang , China |
FANG Jun |
School of Materials Science and Engineering, Shijiazhuang Tiedao University, Shijiazhuang , China |
WEI Wei |
Drainage pipe protection center of Shijiazhuang, Shijiazhuang , China |
ZHANG Shi-wu |
Drainage pipe protection center of Shijiazhuang, Shijiazhuang , China |
LI Yuan-yuan |
Drainage pipe protection center of Shijiazhuang, Shijiazhuang , China |
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Abstract: |
The paper aims to enrich our understanding of the growth law of biofilm and its influence mechanism on the deterioration of concrete in sewage environment. Three types of coatings, namely, inorganic inert coating (IIC), inorganic bactericidal coating (IBC) and organic coating (OC) were applied onto concrete surface, the growth model of biofilm was established based on the measurement of its growth curve, and the microbial community structure of biofilm was observed through confocal laser scanning microscope (CLSM). And then the effect of biofilm on the coated concrete was investigated by measuring the mass change and surface roughness of specimens with and without biofilm. The results show that the mass of biofilm developed on uncoated concrete specimen (UCS) is the highest, followed by IIC, IBC and OC. The growth of biofilm basically follows the surface roughness rule that the rougher the carrier surface is, the more biofilm will be attached, except for IBC. Although the surface roughness of IBC is greater than that of IIC, the biofilm attached on it is less, which indicates that the biological adaptability of the carrier can also affect the growth of biofilm on it. Moreover, compared with that on concrete surface, the attachment stage of biofilm on coating surfaces is longer, whereas its growth stage is shorter. Formula mf= mfe(1–αe–at) can be used as the mathematical model to calculate the mass of biofilm in the attachment stage, and for the growth stage, it also conforms to the Monod equation, that is, the biofilm quality increases linearly with time. As the biofilm can act as a protective layer to a certain degree, the biofilm action coefficient was proposed based on the difference of surface roughness between the samples without and with biofilm attachment after corrosion, and the higher the coefficient is, the stronger the protective effect of biofilm on mortar will be. After 90 days of sewage corrosion, both the mass loss and surface roughness of the specimens without biofilm attachment were higher than that with biofilm attachment, and the biofilm action coefficient of specimen UCS was the highest of 0.67, followed by IIC of 0.51. This indicates that the thick and dense biofilm developed on their surface can act as a physical barrier and reduce the permeability of sewage. For specimens IBC and OC, both of their biofilm action coefficients are lower, just 0.22 and 0.25 respectively, which indicates that the bactericidal and smooth characters of coatings can decrease the growth of biofilm on them and lead to a thinner biofilm layer and more porous biofilm structure, thereby reducing the protective effect. |
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