Research on Improving Concrete Durability by Biomineralization Technology

Round 1

Reviewer 1 Report

Remarks

Please correct:

line 129 - standard cement marking is missing, 3,15 g/cm3

line 263 - show 5 selected subareas

line 283 - unit of given values is missing - MPa

line 308 - should be 17312 coulombs

Author Response

Response to Reviewer 1 Comments

 

Remarks

Please correct:

 

Point 1: line 129 - standard cement marking is missing, 3,15 g/cm³

 

Response: The authors thank the reviewer for his valuable suggestions. The revised manuscript has been corrected.

 

Point 2: line 263 - show 5 selected subareas

 

Response: The 5 selected subareas have been shown in the revised manuscript.

 

Point 3: line 283 - unit of given values is missing - MPa

 

Response: The unit of given values has been shown in the revised manuscript.

 

Point 4: line 308 - should be 17312 coulombs

 

Response: According to the regulations of number format in the journal, the numbers in the revised manuscript are expressed in thousands with a separator.

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

In my opinion if you want write about "Research on Improving Concrete Durability by Biomineralization Technology" you have to make research much longer than 91 days. If you made that type of research you should change the tite of article, because you investigated differences in compressive strength of concrete and ability to self curing after 28 days. 

Can you describe two issue:

what type of external environmental (temperature, humility, the other) is necessary to biomineralization by this bacterias,

how long bacterias are able to make biomineralization (is it still possible after a year, after 10 years, after 50 years ).

Best regards,

Reviewer

Author Response

Response to Reviewer 2 Comments

 

Point 1: In my opinion if you want write about "Research on Improving Concrete Durability by Biomineralization Technology" you have to make research much longer than 91 days. If you made that type of research you should change the title of article, because you investigated differences in compressive strength of concrete and ability to self curing after 28 days.

 

Response: This paper adopted the common methods for studying the durability of concrete, namely the chloride ion permeability test and water permeability test. In addition, using 91-day compressive strength results, so the title of this article focuses on "improving the durability of concrete".

 

Point 2: what type of external environmental (temperature, humidity, the other) is necessary to biomineralization by this bacterias,

 

Response: According to the following literature and the experience of previous experiments, this strain is suitable for survival between 15 and 75 °C, and the optimal reaction temperature range is 20 to 37 °C (this study put them in an oven at 37 °C); pH value between 8-12 is preferred; the humidity of the bacterial solution was 100%.

Chun-Mei Hsu, Yi-Hsun Huang, Vanita Roshan Nimje, Wen-Chien Lee, How-Ji Chen, Yi-Hao Kuo, Chung-Ho Huang, Chien-Cheng Chen and Chien-Yen Chen, 2018. “Comparative Study on the Sand Bioconsolidation through Calcium Carbonate Precipitation by Sporosarcina pasteurii and Bacillus subtilis” Crystals, Vol. 8, No. 189, 1-15, (SCI) Chun-Mei Hsu, Yi-Hsun Huang, How-Ji Chen, Wen-Chien Lee, Hao-Wei Chiu, Jyoti Prakash Maity, Chien-Cheng Chen, Yi-Hao Kuo, Chien-Yen Chen, 2018. “Green synthesis of nano-Co₃O₄ by Microbial Induced Precipitation (MIP) process using Bacillus pasteurii and its application as supercapacitor” Materials Today Communications, Vol. 14, pp.302-311, (SCI) How-Ji Chen, Yi-Hsun Huang, Chien-Cheng Chen, Jyoti Prakash Maity, Chien-Yen Chen, 2019. “Microbial Induced Calcium Carbonate Precipitation (MICP) Using Pig Urine as an Alternative to Industrial Urea”, Waste and Biomass Valorization, 2019, 10, 10, 2887-2895. (SCI)

 

Point 3: how long bacterias are able to make biomineralization (is it still possible after a year, after 10 years, after 50 years).

 

Response: According to the following literature and previous experimental experience, this strain can be mineralized on the first day. As for the speed and duration of the reaction, it depends on the concentration of the bacterial solution and the amount of reaction solution provided. If the nutrient or calcium source in the reaction solution is used up, the reaction stops. In addition, the strains can survive for more than 10 years.

Chun-Mei Hsu, Yi-Hsun Huang, Vanita Roshan Nimje, Wen-Chien Lee, How-Ji Chen, Yi-Hao Kuo, Chung-Ho Huang, Chien-Cheng Chen and Chien-Yen Chen, 2018. “Comparative Study on the Sand Bioconsolidation through Calcium Carbonate Precipitation by Sporosarcina pasteurii and Bacillus subtilis” Crystals, Vol. 8, No. 189, 1-15, (SCI) Chun-Mei Hsu, Yi-Hsun Huang, How-Ji Chen, Wen-Chien Lee, Hao-Wei Chiu, Jyoti Prakash Maity, Chien-Cheng Chen, Yi-Hao Kuo, Chien-Yen Chen, 2018. “Green synthesis of nano-Co₃O₄ by Microbial Induced Precipitation (MIP) process using Bacillus pasteurii and its application as supercapacitor” Materials Today Communications, Vol. 14, pp.302-311, (SCI) How-Ji Chen, Yi-Hsun Huang, Chien-Cheng Chen, Jyoti Prakash Maity, Chien-Yen Chen, 2019. “Microbial Induced Calcium Carbonate Precipitation (MICP) Using Pig Urine as an Alternative to Industrial Urea”, Waste and Biomass Valorization, 2019, 10, 10, 2887-2895. (SCI)

Author Response File: Author Response.docx

Reviewer 3 Report

The paper is important, well written, and focuses on an interesting topic. However, it needs few corrections. For example, please add a photo for water permeability test setup and the chloride ion penetration test. In addition, I noticed that the results were presented without comparisons with other researchers in literature. Comments should be added about the effect of bacteria and biomineralization on different durability aspects, i.e the difference in the response of chloride penetration and the water permeability to the addition of these materials.

Author Response

Response to Reviewer 3 Comments

 

The paper is important, well written, and focuses on an interesting topic. However, it needs few corrections. For example, please add a photo for water permeability test setup and the chloride ion penetration test. In addition, I noticed that the results were presented without comparisons with other researchers in literature. Comments should be added about the effect of bacteria and biomineralization on different durability aspects, i.e. the difference in the response of chloride penetration and the water permeability to the addition of these materials.

 

Point 1: Please add a photo for water permeability test setup and the chloride ion penetration test.

 

Response: In the revised manuscript, photos of water permeability test and chloride ion penetration test have been added.

 

Point 2: In addition, I noticed that the results were presented without comparisons with other researchers in literature. Comments should be added about the effect of bacteria and biomineralization on different durability aspects, i.e. the difference in the response of chloride penetration and the water permeability to the addition of these materials.

 

Response: In the revised manuscript, the test results have been compared with other studies in the literature. The following sentences have been added to the revised manuscript.

It can also be seen in Table 3 that the strength at each age of experimental group I was about 6.7%-32.8% higher than that of the control group. This result is similar to that of Balam et al [37]. The results of the experiments by Balam et al showed that at ages higher than 28 days and when bacteria were used in lightweight aggregate concrete, the growth of relative compressive strength of concrete increased; it came up to 21.5% and 26.4% at ages of 90 days and 150 days, respectively [37]. As can be seen from Table 4, the average permeation depths of the control group, experimental group I, and experimental group II were 34, 20, and 13 mm, respectively. The results show that, regardless of the curing method, the cracked concrete specimens containing biological bacteria can reduce the water penetration depth in concrete. This result is consistent with the study by Balam et al [37]. The average electric flux of experimental group I was 17,312 Coulombs, which was about 9.1% lower than that of the control group. The average electric flux of experimental group II was 17,157 coulombs, which was about 9.9% lower than that of the control group. This result is similar to that of Wu et al [39]. The results of their experiments showed that the chloride ion permeability rate of specimens cultured in bacterial liquids could be reduced by 10.9% [39]. Balam, N.H.; Mostofinejad, D.; Eftekhar, M. Effects of bacterial remediation on compressive strength, water absorption, and chloride permeability of lightweight aggregate concrete. Construction and Building Materials 2017, 145, 107–116. Wu, M.; Hu, X.; Zhang, Q.; Xue, D.; Zhao, Y. Growth environment optimization for inducing bacterial mineralization and its application in concrete healing. Construction and Building Materials 2019, 209, 631–643.

Author Response File: Author Response.docx