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...

Early cracking of cementitious materials based on the eccentric ring test

An improved method based on the ring test called eccentric ring test is used to study the cracking of cementitious materials. The water-cement ratios were 0.25, 0.30, 0.35, 0.4 and the aggregate mass fractions were 10%, 30%, 50%, respectively. It was found that with the increase of water-cement ratio and aggregate, the cracking time of the...

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

Development of self-healing granules having semi-capsulation effect by using cement compound, chemical/mineral admixtures & its watertight performance through crack

Granulation technique, introducing the self-healing ability to concrete, was developed by Koide, 2010 [1] based on the capsulation technology in the food/medicine industry. In this research, self-healing granules, containing cement compounds, chemical and mineral admixtures, were fabricated by a proposed granulation process and the capability of...

Self crack healing induced by high temperature oxidation in SiN/SiC nano-laminated film

In bulk, Si3N4 reinforced by dispersing SiC particle has superior self crack healing ability at high temperature. In consideration with this fact, SiN/SiC nano-laminated film is expected to exhibit the self crack healing at high temperature. In this study, we investigated the self crack healing behavior of the SiN/SiC nano-laminated film...

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...

Resistance of cracked concrete healed by means of polyurethane against chloride penetration

A lot of damage is reported for constructions in marine environments. Marine environments are very aggressive, because of the high chloride concentration in sea water. Chlorides affect durability by initiating corrosion of the reinforcement steel. When cracks appear in the concrete structures, chlorides will penetrate faster and will initiate...

Crack self-healing effect on performance of reinforced concrete members subjected to water supply and cyclic loading

Self-healing concrete (SHC) can heal itself from cracks and other minor imperfections and thus prolong the life of the material itself and structure. In plain and reinforced concrete structures, fatigue is one of the major causes of both material and structural failures. Under the moving load due to traffic, it is not only the relatively simple...

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)