Assessment of self-healing behavior of polypropylene fiber-reinforced cement mortar with crystalline admixture: the effects of crack widths, cracking ages, and external conditions

Crystalline admixture (CA) is an effective self-healing agent for mortar. However, the effects of crack parameters (i.e. crack width and cracking age) and the service environment on the self-healing behavior of CA-containing mortar are not well understood. Herein, the self-healing behavior of mortar containing a self-developed CA was assessed...

Evaluation of acoustic emission source localization accuracy in concrete structures

Acoustic emission source localization is a promising monitoring technique for concrete structures. However, the accuracy of acoustic emission source localization is influenced by many factors, such as the presence of cracks, which are commonly observed in existing reinforced concrete structures. In this article, the acoustic emission source...

Root cause analysis of surface cracks in heavy steel plates during the hot rolling process

This paper investigates the root cause of the formation of surface cracks on hot-rolled C-Mn constructional steel heavy plates. Cracks are rather evenly distributed over the surface in the form of colonies of cracks. Samples were cut from the heavy plate. The microstructure of samples in the as-cast and hot-rolled states were studied using...

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

Encapsulation-based self-healing technology is an effective method for healing the crack-deteriorated cementitious material. Encapsulation-based self-healing initiates by crack occurrence and progresses by chemical reaction of released self-healing agents in the cracks, which are contained in capsules. In this paper, a review has been...

Residual ultimate strength of offshore metallic pipelines with structural damage – a literature review

Reduction of water permeation through cracks in mortar by addition of bacteria based healing agent

Field performance of bacteria-based repair system: Pilot study in a parking garage

This paper presents the field performance in a parking garage of the recently developed bacteria-based repair system for concrete. This liquid-based repair system aims at the sealing of cracks and decrease of the porosity due to the production of a calcium-based biomineral. The system combines advantages of both a traditional repair system for...

A coupled transport-reaction model for simulating autogenous self-healing in cementitious materials. Part I: Theory

In this study, a coupled transport-reaction model was specifically developed for simulating autogenous self-healing in cementitious materials. The diffusion of ions between the solution in the crack and in the bulk paste is simulated with a transport model. The concentration of ions in the crack can be calculated. As the kinetics of chemical...

A coupled transport-reaction model for simulating autogenous self-healing in cementitious materials. Part II: Validation through comparison with experiments

In this paper, the proposed coupled transport-reaction model adapted to simulate autogenous self-healing in Portland cement paste is validated with the experimental results. The parameters are studied for modelling the dissolution of cement, the diffusion of ions between the solution in the crack and in the bulk paste and the precipitation of...

Shear Resistance of Reinforced Concrete Beams without Shear Reinforcement under Sustained Loading

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

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...

Time-dependent behavior of cracked concrete beams under sustained loading

Under sustained loading, the propagation of cracks in concrete is assumed to be related to the elastic deformation, material parameters and time. Based on the fictitious crack model (FCM), a finite element method is proposed to explain the behavior of cracks in time using current constitutive relations to approximate the time-dependent crack...

Surface crack self healing behaviour of mortars with expansive additives (abstract)