Determination of strength and debonding energy of a glass-concrete interface for encapsulation-based self-healing concrete

Abstract

This paper presents a combined experimental-numerical analysis to assess the strength and fracture toughness of a glass-concrete interface. This interface is present in encapsulation-based self-healing concrete. There is absence of published results of these two properties, despite their important role in the correct working of this self-healing strategy. Two setups are used: uniaxial tensile tests to assess the bonding strength and four point bending tests to get the interfacial energy. The complementary numerical models for each setup are conducted using the finite element method. Two approaches are used: cohesive zone model to study the interface strength and the virtual crack closure technique to analyze the interfacial toughness. The models are validated and used to verify the experimental interpretations. It is found that a glass-concrete interface can develop a maximum strength of approximately 1 N/mm 2 with fracture energy of 0.011 J/m 2 .

Macro- and micro-modeling of crack propagation in encapsulation-based self-healing materials: Application of XFEM and cohesive surface techniques

“…The maximum interface tensile strength (σ * i ) formed between concrete matrix and glass capsules, hereafter referred to as bonding strength, provides a measure of the static normal load required to separate a piece of concrete fully adhered to a flat glass surface. The particular values of this interface strength are vaguely reported in the literature, with the exception of some works [51,52]. In these works, a glass-concrete interface was created just placing a conventional glass plate in contact with fresh concrete, and allowing the bimaterial sample to cure as usually done with pieces only made of concrete.…”

Modelling the fracture behaviour of thermal barrier coatings containing healing particles

“…Secondly, it is essential to study how the healing particles influence the thermomechanical behaviour of the self-healing TBC in comparison with the baseline TBC without healing particles, in other words, introducing healing particles should not significantly deteriorate the mechanical integrity of the original TBC system. Several modelling studies have been conducted in the literature to address the above two aspects [22][23][24][25][26][27]. For instance, the influence of mechanical properties of the healing particles on the fracture mechanism in a self-healing material have been analysed in detail in [28,27].…”

A review study on encapsulation‐based self‐healing for cementitious materials

“…However, the specific value of bonding strength was not determined in this art of paper. Therefore, latterly, an axisymmetric 3D finite model was built to assess strength and fracture toughness of glass‐concrete interface . The verified interface bonding strength is 0.96 ± 0.09 N/mm 2 calculated by cohesive zone model, and the interfacial energy is 10.62 ± 0.02 mJ/m 2 obtained by virtual crack closure technique.…”

“…The healing principle of encapsulation‐based self‐healing concrete heavily relies on the immediate rupture of prior inserted capsules, the flow of internal healing agents into crack location and the following adequate curing reactions . Therefore, to guarantee high efficient self‐healing, these three subprocesses must be promptly activated .…”