TY - JOUR U1 - Wissenschaftlicher Artikel A1 - Gao, Miaomiao A1 - Guo, Jia A1 - Cao, Hui A1 - Wang, Huqun A1 - Xiong, Xin A1 - Krastev, Rumen A1 - Nie, Kaili A1 - Xu, Haijun A1 - Liu, Luo T1 - Immobilized bacteria with pH-response hydrogel for self-healing of concrete JF - Journal of environmental management N2 - Concrete is significant for construction. A problem in application is the appearance of cracks that will damage its strength. An autogenous crack-healing mechanism based on bacteria receives increasing attention in recent years. The bacteria are able to form calcium carbonate (CaCO3) precipitations in suitable conditions to protect and reinforce the concrete. However, a large number of spores are crushed in aged specimens, resulting in a loss of viability. A new kind of hydrogel crosslinked by alginate, chitosan and calcium ions was introduced in this study. It was observed that the addition of chitosan improved the swelling properties of calcium alginate. Opposite pH response to calcium alginate was observed when the chitosan content in the solution reached 1.0%. With an addition of 1.0% chitosan in hydrogel beads, 10.28% increase of compressive strength and 13.79% increase of flexural strength to the control were observed. The results reveal self-healing properties of concretes. A healing crack of 4 cm length and 1 mm width was observed when using cement PO325, with the addition of bacterial spores (2.54–3.07 × 105/cm3 concrete) encapsulated by hydrogel containing no chitosan. KW - self-healing KW - concrete KW - spores KW - calcium alginate KW - chitosan KW - crosslink Y1 - 2020 SN - 0301-4797 SS - 0301-4797 U6 - https://doi.org/10.1016/j.jenvman.2020.110225 DO - https://doi.org/10.1016/j.jenvman.2020.110225 VL - 261 SP - 1 EP - 6 S1 - 6 PB - Elsevier CY - Amsterdam ER -