Aerobic bacteria induced biomineralization: effects of nutrient and calcium content on the nanostructure and chemical composition of simulated cement mixture
Linzhen Tan , Jiacheng Zhang , Jing Xu , Binling Chen , Baosen Mi , Yongqi Wei , Wu Yao
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引用次数: 0
Abstract
During the past two decades, aerobic bacteria induced biomineralization has gained popularity for autonomous sealing of cracks in concrete structures due to its environmentally friendly characteristics of carbon retention. However, the mechanism of the biomineralization induced by aerobic bacteria for concrete crack sealing is still unclear due to the complex chemistry of cement matrix. Also, as the main nutrient for bacterial growth, the effect of yeast extract (YE) on biomineralization should be properly evaluated. For the first time, this study investigates the effects of YE and calcium content on the development of nanostructure and chemical composition of cement matrix during the biomineralization process induced by aerobic bacteria Bacillus cohnii. The effects of calcium content were realized by constructing a simulated cement mixture consisting of calcium hydroxide and synthesised C-S-H with different C/S ratios. The effects of YE content were evaluated by the addition of different amounts of YE into simulated cement mixture with different C/S ratios. Results suggest that 10g/l of YE can cause a high pH value of 10 and an unsuccessful growth of bacteria in simulated cement mixture with C/S ratios 0.6 and 0.8. Upon increasing the YE from 10 g/l to 20 g/l, the pH reduced from 10 to 9 and the bacteria was successfully grown. Higher amounts of bicarbonate ions can cause an enhanced decalcification of synthesised C-S-H rather than calcium hydroxide. The aerobic bacteria Bacillus cohnii showed superior performance on calcium absorption and calcite precipitation, being a promising way for practical concrete crack sealing.
期刊介绍:
Cement & concrete composites focuses on advancements in cement-concrete composite technology and the production, use, and performance of cement-based construction materials. It covers a wide range of materials, including fiber-reinforced composites, polymer composites, ferrocement, and those incorporating special aggregates or waste materials. Major themes include microstructure, material properties, testing, durability, mechanics, modeling, design, fabrication, and practical applications. The journal welcomes papers on structural behavior, field studies, repair and maintenance, serviceability, and sustainability. It aims to enhance understanding, provide a platform for unconventional materials, promote low-cost energy-saving materials, and bridge the gap between materials science, engineering, and construction. Special issues on emerging topics are also published to encourage collaboration between materials scientists, engineers, designers, and fabricators.