Air-entraining admixtures as a protection method for bacterial spores in self-healing cementitious composites: Healing evaluation of early and later-age cracks
Air-entraining admixtures as a protection method for bacterial spores in self-healing cementitious composites: Healing evaluation of early and later-age cracks
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DOI：
10.1016/j.conbuildmat.2022.126877
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发表时间：
2022-02-24
影响因子：
7.4
通讯作者：
Paine, Kevin
中科院分区：
文献类型：
--
作者：
Justo-Reinoso, Ismael;Reeksting, Bianca J. J.;Paine, Kevin
与细菌孢子的包封过程相关的成本仍然是自修复水泥材料商业化的限制因素。评估了使用加气混合物（AEAs）作为细菌孢子的经济且直接的包封方法的可行性，以愈合在早期（28天）或后期（9个月）形成的裂缝（~ 0.50 mm）。将混凝土工业中常用的三种AEA与一种成功证明的保护方法（即，通过加气混凝土颗粒（ACG））。在这方面，与使用封装在ACG中的细菌孢子的等效混合物相比，研究的三种AEA中只有一种改善了愈合性能。愈合率与此成功的AEA获得59.6%和46.2%，高于观察到的结果为ACGs的混合物时，开裂年龄分别为28天和9个月。此外，对于早期或后期形成的裂缝，在愈合56天后，水渗透阻力分别增加了18.1%或呈现非常相似的值（-84%）。此外，进行了简单的成本分析，以确认使用AEAs保护直接添加的细菌孢子的显着经济效益。在这方面，使用积极评价的成本比ACG低约13倍。因此，这项研究首次提供了使用AEAs保护细菌孢子的可行性证据，为定制AEAs的开发打开了大门，以设计具有成本效益的自愈合胶凝材料。
Costs associated with the encapsulation process of bacterial spores continue to be a limiting factor for the commercialisation of self-healing cementitious materials. The feasibility of using air-entraining admixtures (AEAs) as an economical and straightforward encapsulation method for bacterial spores was evaluated to heal cracks (-0.50 mm) that were formed at an early (28 days) or later age (9 months). Three AEAs, commonly used in concrete industry, were compared to a successfully proven protection method (i.e., via aerated concrete granules (ACGs)). In this regard, only one of the three AEAs investigated improved the healing performance when compared to an equivalent mix using bacterial spores encapsulated in ACGs. Healing ratios obtained with this successful AEA were 59.6% and 46.2% higher than the results observed for the ACGs-containing mix when the cracking age was 28 days and 9 months, respectively. Moreover, water penetration resistance was increased by 18.1% or presented very similar values (-84%) after 56 days of healing for early or later-formed cracks, respectively. Moreover, a simple cost analysis was conducted to confirm the significant economic benefits of using AEAs to protect directly added bacterial spores. In this regard, the cost of using AEAs is about 13 times lower than for ACGs. Therefore, this study provides for the first time, evidence of the feasibility of using AEAs to protect bacterial spores, opening the doors to the development of bespoke AEAs to design cost-efficient selfhealing cementitious materials.