A chitosan based pH-responsive hydrogel for encapsulation of bacteria for self-sealing concrete. (October 2018)

• Record Type: Journal Article
• Authors: Wang, Jianyun; Mignon, Arn; Trenson, Gilles; Van Vlierberghe, Sandra; Boon, Nico; De Belie, Nele
• Is Part Of: Cement & concrete composites. Volume 93(2018)
• Page Start: 309
• Page End: 322
• Publication Date: 2018-10
• Subjects: pH responsive -- Hydrogel -- Bacteria -- Crack -- Water flow -- Bio-CaCO3; Composite-reinforced concrete -- Periodicals; Concrete -- Periodicals; Composite materials -- Periodicals; Composites de ciment -- Périodiques; Béton -- Périodiques; Composites -- Périodiques; Béton léger -- Périodiques; Cement composites; Composite materials; Composite-reinforced concrete; Concrete; Lightweight concrete; Periodicals; Electronic journals; 620.135
• DOI: 10.1016/j.cemconcomp.2018.08.007
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: Cracks in concrete remain one of the major issues in constructions. Self-healing concrete by bacteria has already proven to be a promising way to solve this problem. In order to protect bacteria from the harsh condition in concrete, encapsulation of bacteria is preferable. In this study, a pH responsive hydrogel was synthesized to encapsulate bacterial spores for self-sealing concrete cracks. The pH responsiveness and the influence of the hydrogel on the mechanical properties were investigated. The viability of the encapsulated spores and the cell-entrapping capacity of the hydrogel were then examined. The self-sealing efficiency was evaluated by the reduction of water flow and crack sealing ratio. The results indicated that the chitosan based hydrogel had a suitable pH responsiveness. Within the pH range between 7 and 11, the swelling capacity remained stable, with no significant differences as the swelling varied between 38.5 ± 0.5 and 42.9 ± 1.5 g water/g hydrogel. The swelling greatly decreased to around 12.8 ± 0.9 g water/g hydrogel in cement filtrate. The compressive strength only decreased around 5% with the addition of 1 m% of hydrogel. The specimens with hydrogel encapsulated spores showed the highest reduction in water flow (81–90%) and highest crack sealing efficiency. More than 30% of the crack locations was completely bridged. While in other specimens, only 2–12% of the crack locations was completely sealed.