Strain-Hardening Cementitious Composite (SHCC) For Durable Concrete Repair

Infrastructure is ageing and we are facing a serious challenge on how to deal with it. One possible solution is to repair it, but the life of current concrete repairs, including all types of repairs and application of different materials, is not satisfactory and there is an urgent need for improvement. Understanding the damage development in a...

Micro-Cantilever Testing Of Cementitious Materials Under Various Loading Conditions

Nanoindentation is usually used to investigate local elastic properties and hardness of materials. In this paper, the nanoindenter served as a loading tool to perform micro scale bending tests and measure the global response of micro-scale specimens. For testing, cement paste cantilever beams with a square cross-section of 300 μm × 300 μm were...

Numerical analysis of effect of micro-cracking and selfhealing on the long-term creep of cementitious materials

In order to gain a better understanding of the interaction between creep and micro-cracking during long-term creep process, a theoretical study was performed. An existing lattice model was modified to take creep into account. Based on the model, the micro-cracking in the creep process was simulated on a three-phase concrete sample under...

Potentiometric response of Ag/AgCl sensor in Portland and slag cement pastes

Determination of the free chloride content in a concrete structure is important for evaluation of the risk of corrosion of reinforcing steel. The Ag/AgCl sensor is sensitive to chloride ions and exhibits an open circuit potential (OCP) that depends on the chloride ions activity in the environment. The interference of hydroxide and sulfide ions...

Long-term performance of marine structures in the Netherlands - validation of predictive models for chloride ingress

For many concrete infrastructural works a service life of 80, 100 or 200 years is required. To convince owners and authorities that these requirements can be met probability-based models for service life predictions have been developed. These models are based on theoretical and experimental laboratory studies. Many of these models focus on...

Stray current vs anodic polarization in reinforced mortar: a comparative study on steel corrosion behaviour in both regimes

Stray current arising from direct current electrified traction systems and then circulat-ing in reinforced concrete structures may initiate corrosion or even accelerate existing corrosion processes on embedded reinforcement. Therefore, stray-current induced corrosion of nearby reinforced concrete structures deserves more attention in view of...

Effect of corrosion on the fatigue service-life on steel and reinforced concrete beams

Chloride-induced corrosion is a point of big concern in reinforced concrete (RC) structures. To monitor the actual health and to predict the remaining service-life of structures, it is important to understand the structural behaviour and the failure mechanism of structures exposed to chlorides under fatigue loading conditions. A beam test,...

Potentiometric response of chloride sensors in cementitious materials of varying chemical composition and water-to-cement ratio

Free chloride ions are the main cause of steel corrosion in reinforced concrete structures. Ag/AgCl electrodes, as chloride sensors, are predominantly sensitive to chloride ions and respond electrochemically to the chloride ion activity in the environment. This is reflected by changes of the open circuit potential (OCP) of the sensors. To...

A modelling study of drying shrinkage damage in concrete repair systems

Differential shrinkage between repair material and concrete substrate is considered to be the main cause of premature failure of repair systems (Martinola, Sadouki et al. 2001, Beushausen and Alexander 2007). Magnitude of induced stresses depends on many factors, for example the amount of restraint, moisture gradients caused by different curing...

Evaluation of Ag/AgCI sensors for in-situ monitoring of freee chloride concentration in reinforced concrete structures

The level of free chloride concentration in reinforced concrete structures essentially determines the onset of steel corrosion initiation and further propagation. One of the well-known methods for monitoring free chloride concentration is using silver/silver chloride electrodes (Ag/AgCl). These electrodes are sensitive mainly to chloride ions...

Nondestructive determination of chloride concentration using Ag|AgCl electrodes produced by electrochemical anodization

The stability of chloride ion selective electrodes in highly alkaline solutions is an important aspect when reliability and feasibility within reinforced concrete applications are concerned. The sensitivity of these electrodes largely depends on the properties of the AgCl layer, including uniformity, porosity, orientation, thickness, etc. These...

Non-destructive evaluation of chloride-induced corrosion in reinforced concrete: Electrochemical impedance spectroscopy sheds new light on generally applied sensors performance

Service life of reinforced concrete structures exposed to chloride enriched environment is well known to be mainly determined by steel passivity breakdown in the event of chloride-induced corrosion initiation and propagation. Since Cl- induced (localized) corrosion is caused by the free (water-soluble) chloride, present in the pore network of a...

Characterization of Portland cement paste using MIP, nanoindentation and esem techniques

The influence of pluronic P123 micelles on corrosion behaviour of steel in cement extract and bulk matrix properties of cement paste

The influence of Pluronic P123 (PEO20-PPO20-PEO70) micelles (of 10 nm size) on the corrosion behaviour of low carbon steel in cement extract (CE) was studied using electrochemical impedance spectroscopy (EIS) and potentio-dynamic polarisation (PDP). Additionally, mercury intrusion porosimetry (MIP) was emplo ed to derive the impact of admixed...

Tailor-made nano materials for corrosion control and improved matrix characteristics in cement-based systems

The effect of electrical current flow on cement-based microstructure: Bulk matrix alterations within cathodic protection in reinforced concrete