Junwale Rishabh, Bhutange Snigdha P, Latkar Madhuwanti
Department of Civil Engineering, Visvesvaraya National Institute of Technology (VNIT), Nagpur, Maharashtra, 440010, India.
Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, 400076, India.
Mol Biotechnol. 2025 Jan 29. doi: 10.1007/s12033-025-01375-y.
Recently biocementation has got attention of many researchers worldwide as one of the most potent techniques for sustainable construction. Several studies have been carried out worldwide on biocementation by urea hydrolysis. Biocementation by bacterially induced calcium carbonate precipitation by different bacterial species has been among the most widely researched areas in this field. Biocementation has proved efficient in enhancing the strength and durability of cement-based materials. However, no significant work has been carried out to determine the performance of biocemented specimens at elevated temperatures. This study primarily focuses on the effects of high temperatures (300, 450, and 600 °C) on the compressive strength of two types of biocemented specimens prepared by using ureolytic bacteria and rich in urease watermelon seeds. The motive behind testing these two types is to know how the enzyme induced or microbially induced react to temperature elevation. Also, the effect of different cooling techniques (viz., natural cooling, water spray cooling and fire extinguishing foam spray cooling) were studied. These cooling techniques were selected so as to check which cooling technique should be preferred in case of fire situation in a cement-based structure. Results show that biocemented specimens can perform very good up to the temperature 300 °C as compared to control specimens in terms of compressive strength. At 450 °C temperature, there is no significant difference in compressive strengths of control and biocemented specimens. When the specimens were subjected to 600 °C, biocemented specimens showed lower strength than control specimens at the same temperature due to denser microstructures. Thus, biocemented cement mortar should not be used in reactors, muffles and ovens where temperature would go above 450 °C.
最近，生物胶结作为可持续建筑最有效的技术之一，受到了全球众多研究人员的关注。世界各地已经开展了多项关于尿素水解生物胶结的研究。不同细菌物种通过细菌诱导碳酸钙沉淀进行生物胶结，一直是该领域研究最广泛的领域之一。生物胶结已被证明在提高水泥基材料的强度和耐久性方面是有效的。然而，尚未开展大量工作来确定生物胶结试件在高温下的性能。本研究主要关注高温（300、450和600℃）对两种使用尿素分解菌和富含脲酶的西瓜籽制备的生物胶结试件抗压强度的影响。测试这两种类型的背后动机是了解酶诱导或微生物诱导对温度升高的反应。此外，还研究了不同冷却技术（即自然冷却、喷水冷却和灭火泡沫喷雾冷却）的效果。选择这些冷却技术是为了检查在水泥基结构发生火灾时应优先采用哪种冷却技术。结果表明，与对照试件相比，生物胶结试件在300℃以下的温度下抗压强度表现非常好。在450℃时，对照试件和生物胶结试件的抗压强度没有显著差异。当试件承受600℃时，由于微观结构更致密，生物胶结试件在相同温度下的强度低于对照试件。因此，生物胶结水泥砂浆不应用于温度会超过450℃的反应器、马弗炉和烤箱中。
