Interaction between microcapsules and cementitious matrix after cracking in a self-healing system

Interaction between microcapsules and cementitious matrix after cracking in a self-healing system

Wang, X.
Xing, F.
Zhang, M.
Han, N.
Qian, Z.

Civil Engineering and Geosciences

Structural Engineering

2013-06-16

A new type of self-healing cementitious composites by using organic microcapsules is designed in Guangdong Key Laboratory of Durability for Coastal Civil Engineering, Shenzhen University. For the organic microcapsules, the shell material is urea formoldehyde (UF), and the core healing agent is Epoxy. The effect of organic microcapsules on mechanical behaviors of the composite specimens and the interaction between an organic microcapsule and an approaching crack is investigated in this study. The mechanical behaviors of bending and compression strengths for mortar specimens are tested. The results show that the strength may increase with a small amount of microcapsules and then decrease with increasing of microcapsules. The FEM numerical simulation is carried out to study the interaction between a crack and a microcapsule in the concrete matrix. It is known that there exist two possibilities when a crack approaches a microcapsule, the microcapsule is ruptured or debonded from the matrix. The self-healing function is based on the rupture of microcapsules. Thus determination of judgment criterion (The physical trigger mechanism-cracking) that under what condition a microcapsule ruptures is necessary. For simplicity, a two-dimensional plane square area is considered, in which the side length is 1 cm. A microcapsule of radius 0.1mm is located at the center of the area. Left hand side is a line crack. The interface between the microcapsule and the mortar matrix, as well as the bonding behavior of the microcapsule shell wall is modeled using the cohesive traction-separation constitutive relationship. The actual parameters of the materials may lead to rupture or debonding of a microcapsule. Through numerical simulation, the criterion of the possible failure pattern for a microcapsule is obtained in terms of the intensity of microcapsule wall, the intensity of the interface, thickness of the microcapsule wall, location of the crack, and the microcapsule radius.

self-healing concrete
organic microcapsules
interaction
crack
debonding

http://resolver.tudelft.nl/uuid:7a74cc18-967f-42a4-8b77-7948eb2c3a57

Magnel Laboratory for Concrete Research

9789082073713

uuid:3078d20c-2173-4c13-a4d7-106207c78577

ICSHM 2013: Proceedings of the 4th International Conference on Self-Healing Materials, Ghent, Belgium, 16-20 June 2013

Institutional Repository

conference paper

(c) 2013 The Author(s)