Mechanical properties of bio self-healing concrete containing immobilized bacteria with iron oxide nanoparticles

Abstract

Concrete is arguably one of the most important and widely used materials in the world, responsible for the majority of the industrial revolution due to its unique properties. However, it is susceptible to cracking under internal and external stresses. The generated cracks result in a significant reduction in the concrete lifespan and an increase in maintenance and repair costs. In recent years, the implementation of bacterial-based healing agent in the concrete matrix has emerged as one of the most promising approaches to address the concrete cracking issue. However, the bacterial cells need to be protected from the high pH content of concrete as well as the exerted shear forces during preparation and hardening stages. To address these issues, we propose the magnetic immobilization of bacteria with iron oxide nanoparticles (IONs). In the present study, the effect of the designed bio-agent on mechanical properties of concrete (compressive strength and drying shrinkage) is investigated. The results indicate that the addition of immobilized Bacillus species with IONs in concrete matrix contributes to increasing the compressive strength. Moreover, the precipitates in the bio-concrete specimen were characterized using scanning electron microscope (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). The characterization studies confirm that the precipitated crystals in bio-concrete specimen were CaCO, while no precipitation was observed in the control sample.

Microbially induced calcium carbonate precipitation: a widespread phenomenon in the biological world

“…This phenomenon significantly decreases their effectiveness to heal the cracks in hardened concrete. Recently, attempts have been made to introduce the biological healing agent (including bacteria and nutrients) into the concrete matrix during concrete preparation (Seifan et al 2018c;Seifan et al 2018d). However, the protection of bacteria from stresses in alkaline environment of concrete to induce a high affinity of calcium carbonate has remained a challenge (Wang et al 2012b).…”

“…Arunachalam et al 2010;De Muynck et al 2008a;De Muynck et al 2008b;De Muynck et al 2013;Dick et al 2006;Kim et al 2013;Seifan et al 2018a;Seifan et al 2018b;Seifan et al 2018c;Seifan et al 2018d;Seifan et al 2016b;Seifan et al 2017a;Seifan et al 2017b;Seifan et al 2017c;Van Tittelboom et al 2010;Wang et al 2012a; …”

Development of an Innovative Urease-Aided Self-Healing Dental Composite

“…The precipitation of CaCO 3 to develop self-healing materials has been previously explored in different fields including construction [13][14][15][16]. For example, microbially induced CaCO 3 precipitation (MICP) via hydrolysis of urea as a consequence of the urease positive microorganism's metabolism has been examined for designing self-healing cementitious composites [17,18], improvement of soil properties [19], and remediation of environmental contaminants [20]. Urease is a high molecular weight enzyme, and the salient feature of it is the active site that contains a bi-nickel center [21].…”

Effect of Mill-Rejected Granular Cement Grains on Healing Concrete Cracks

“…Self-healing mechanisms in concrete are categorized as autonomous and autogenous. Autonomous self-healing concrete is designed to heal its cracks using special additives such as bacteria in bioremediation techniques [13][14][15][16][17][18][19][20], fiber in fiber-reinforced strain-hardening cementitious composites [10,[21][22][23][24], supplementary cementitious materials (fly ash, silica fume, blast-furnace slag, etc.) [25], geo-materials in the form of powder, and an expansive agent, which expands and fills the crack void [26,27].…”