BIOMIMETIC MULTI-SCALE DAMAGE IMMUNITY FOR CONCRETE: THE CONTRIBUTION OF BACTERIA-BASED SELF-HEALING

Author(s): Kevin Paine, Andrew Heath, Richard Cooper and Susanne Gebhard
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: 583
Total Pages: 308
Language : English

Abstract: A recent UK research project entitled, M4L: Materials for Life, has been investigating ground-breaking and novel developments in the delivery of self-immunity for concrete; including recent advances in multi-scale (~10nm to ~5mm) self-healing and self-recovery systems. Four principal forms of self-healing have been studied: (i) microcapsules, (ii) bacteria, (iii) shape memory polymers and (iv) vascular networks. This paper draws out the developments that have taken place in development of the bacteria-based self-healing concrete within this scope of a multi-scale self-healing system. The paper reports on microbiological characterization of alkaliphilic Bacillus species for spore production, germination and calcite formation, and on cement science studies to understand the effect of nutrients and precursors on setting, hardening and microstructure of cement. A number of methods for encapsulating bacterial spores and nutrients within a concrete matrix were studied including: (i) calcium alginate beads, (ii) porous aggregates, (iii) vascular networks and (iv) microcapsules. It was found that both porous aggregates and microcapsules gave good results. When used in mortars it is shown that encapsulated spores and nutrients provide healing in cracks up to 0.3 mm in size depending on environmental conditions and the concentrations of self-healing agent used. A full-scale site trial investigated the technology in a full-scale site trial and showed that it was possible to mix, place and compact bacteria-based self-healing concrete using conventional practices and that there was no negative effect on mechanical properties. Finally, the paper provides an overview of future anticipated developments as part of a follow on project: Resilient Materials for Life.

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