title: Detecting the activation of a self-healing mechanism in concrete by acoustic emission and digital image correlation.
abstract: Autonomous crack healing in concrete is obtained when encapsulated healing agent is embedded into the material. Cracking damage in concrete elements ruptures the capsules and activates the healing process by healing agent release. Previously, the strength and stiffness recovery as well as the sealing efficiency after autonomous crack repair was well established. However, the mechanisms that trigger capsule breakage remain unknown. In parallel, the conditions under which the crack interacts with embedded capsules stay black-box. In this research, an experimental approach implementing an advanced optical and acoustic method sets up scopes to monitor and justify the crack formation and capsule breakage of concrete samples tested under three-point bending. Digital Image Correlation was used to visualize the crack opening. The optical information was the basis for an extensive and analytical study of the damage by Acoustic Emission analysis. The influence of embedding capsules on the concrete fracture process, the location of capsule damage, and the differentiation between emissions due to capsule rupture and crack formation are presented in this research. A profound observation of the capsules performance provides a clear view of the healing activation process.
authors.affiliation: Department of Mechanics of Materials and Constructions, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium ; SIM vzw-Program SHE, Technologiepark 935, 9052 Zwijnaarde, Belgium.
authors.forename: E
authors.initials: E
authors.lastname: Tsangouri
authors.affiliation: Department of Mechanics of Materials and Constructions, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: D G
authors.initials: DG
authors.lastname: Aggelis
authors.affiliation: Magnel Laboratory for Concrete Research, Department of Structural Engineering, Faculty of Engineering, Ghent University, Technologiepark Zwijnaarde 904, 9052 Ghent, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Van Tittelboom
authors.affiliation: Magnel Laboratory for Concrete Research, Department of Structural Engineering, Faculty of Engineering, Ghent University, Technologiepark Zwijnaarde 904, 9052 Ghent, Belgium.
authors.forename: N
authors.initials: N
authors.lastname: De Belie
authors.affiliation: Department of Mechanics of Materials and Constructions, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: D
authors.initials: D
authors.lastname: Van Hemelrijck
mesh_terms: D000162:Acoustics / Q000295:instrumentation; D003252:Construction Materials / Q000032:analysis*; D008422:Materials Testing / Q000379:methods*; D055595:Mechanical Phenomena; D011140:Polyurethanes / Q000737:chemistry
chemical_list: D011140:Polyurethanes