USING LIGHTWEIGHT AGGREGATES AS A CARRIER FOR BACTERIAL SPORES IN SELF-HEALING CONCRETE

Author(s): Chen-Hsuan Chiu, Chien-Chung Chen and W.T. Evert Ting
Paper category: Proceedings
Book title: Proceedings of the Final Conference of RILEM 253-MCI Microorganisms-Cementitious Materials Interactions Volume II
Editor(s): Alexandra Bertron and Henk Jonkers
ISBN: 978-2-35158-207-7 (Set)
ISBN: 978-2-35158-210-7 (Volume 2)
e-ISBN: 978-2-35158-206-0
Publisher: RILEM Publications SARL
Publication year: 2018
Pages: 465-473
Total Pages: 308
Language : English

Abstract: Bacteria-based self-healing concrete incorporates alkaline resistant bacterial spores into concrete mix. To enhance survival in the harsh concrete environment, bacterial spores have been impregnated into various protective carriers. A previous study showed that immobilizing spores in expanded clay (EC), a type of lightweight aggregates (LWA), extended concrete healing performance. In this study, two types of LWA, expanded shale (ES) and EC were used as carriers for bacterial spores and compared for their ability to enhance survival of bacterial spores in mortar samples. Each type of LWA was also separated into three sizes (<0.85 mm, 0.85~2.0 mm, and >2.0 mm) and evaluated individually. Spores of Bacillus cohnii and B. pseudofirmus were first embedded into LWA separately and dried. It was found that viable spore counts reduced about 1 log during the process of embedding spores into LWA but remained constant thereafter. Viable counts recovered from EC and ES were about the same. Small sized LWA in general retained more spores. The LWA with immobilized spores were used to make mortar samples. Mean viable counts dropped 3.0~3.9 logs after 28 days. It appeared that neither EC nor ES effectively protected the two types of bacterial spores from death in mortar samples.

Online publication : 2018
Publication type : full_text
Public price (Euros) : 0.00