Effect of biomineralized Bacillus subtilis on recycled aggregate concrete containing blended hydrated lime and brick powder

Bakr, Mohd Abu; Singh, B. K.

doi:10.1016/j.cscm.2023.e02137

Cited by 5 publications

(10 citation statements)

References 43 publications

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“…The current self-healing outcomes are associated with previous studies. 1,4,6,24,31,34 These findings validate the effectiveness of RCA as a carrier technology in promoting bacterial self-healing concrete.…”

Section: Quantification Of Crack Healingsupporting

confidence: 58%

“…The previous literature reveals that the direct incorporation of Bacillus bacteria has become very longstanding to enhance the strength and durability properties of RAC. 23,24,[62][63][64][65][66] However, most of the researchers further analyzed the self-healing efficiency through the biomineralization technique, in which with time the bacterial efficacy was reduced. 8 Despite extensive research conducted on the self-healing mechanism, bacterial consortium immobilized RCA has not been explicitly explored.…”

Section: Research Significancementioning

confidence: 99%

“…The EDS results of the current study are in good agreement with the previous research. 6,24,84 This substantial calcium presence, evenly distributed throughout the concrete matrix, serves to foster the sustained viability and harmonious integration of both the pure culture of bacteria and their consortium within the concrete matrix over extended periods.…”

Section: Microstructural Analysismentioning

confidence: 99%

“…[19][20][21][22] The most prevalent ureolytic bacteria are Bacillus sphaericus, megaterium and pasteurii, which can hydrolyse the urea into calcite carbonate through metabolic processes. [23][24][25][26] Ammonium can also result from the process of urea hydrolysis, a situation that holds the potential to harm the environment and negatively impact human health. [27][28][29] These problems may be successfully avoided by the respiration techniques used by these non-ureolytic bacteria like Bacillus cohnii and pseudofirmus which metabolize the organics into the calcium carbonate, which is more eco-friendly.…”

Section: Introductionmentioning

confidence: 99%

“…RCA containing tightly bonded adhered mortar to their surface, causes them to absorb more water and have less strength than natural coarse aggregates (NCA). 24,46,47 In recent times, researchers have made efforts to utilize RCA as carriers for microbes in the development of self-healing concrete, primarily due to its porous characteristics. [48][49][50] Liu et al 33 employed RCA as a carrier for Bacillus pasteurii to assess the effectiveness of bacterial concrete in terms of self-healing.…”

Section: Introductionmentioning

confidence: 99%

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Effects of bacterial consortium enhanced recycled coarse aggregates on self‐healing concrete immobilized with Bacillus megaterium MTCC 1684 and Bacillus subtilis NCIM 2193

Bakr,

Hussain,

Singh

et al. 2023

Structural Concrete

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The strength and durability properties of the recycled aggregate concrete (RAC) have been affected by the cracks and the weak interfacial transition zone (ITZ) of the recycled coarse aggregates (RCA). However, the mechanical and physical features of RCA can be improved by microbially induced calcite precipitation (MICP). Therefore, immobilization techniques were used to protect and maintain the high efficiency of Bacillus bacteria for the formation and precipitation of calcium carbonates in self‐healing concrete over a period of time. The objective of the present study was to show the viability of the immobilized bacterial consortium‐enhanced RCA to form self‐healing cracks. Further, the self‐healing capability of enhanced RCA was investigated along with two other immobilization methods, that is, RCA and hydrated lime and brick powder (HBr)‐immobilized bacteria. The experimental results show that the increase in the bio‐deposition time improved the physical and mechanical properties of the RCA. Further, subsequently 56 days of the healing incubation period, the immobilized consortium‐enhanced RCA concrete specimens completely healed the cracks of width 0.58 mm. However, the equivalent cracks of width 0.56 mm were also recovered by the HBr immobilized bacterial cultures. Furthermore, the field emission scanning electron microscope (FESEM), energy dispersive spectroscopy (EDS) and X‐ray diffraction (XRD) analysis revealed that the existence of precipitation at the crack surface was calcium carbonate with a regular cubic‐shaped and lamellar layer morphology. The outcomes of the current study show that consortium‐enhanced RCA has promising potential to develop self‐healing concrete with self‐repaired and improved durability properties in the concrete construction field.

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