Failure Modes in Concrete Repair Systems due to Ongoing Corrosion

Corrosion of steel reinforcement is the main cause of deterioration in reinforced concrete structures. It can result in cracking and spalling of the concrete cover. After the damaged cover is repaired, reinforcement corrosion might continue and even accelerate. While the development of the corrosion cell is difficult to control, the damage can...

A 3D Lattice 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. The magnitude of induced stresses depends on many factors, for example the degree of restraint, moisture gradients caused by curing and drying conditions, type of repair material, etc. Numerical...

Carbonation of cement paste: Understanding, challenges, and opportunities

Cement paste is known to react with atmospheric carbon dioxide. Carbonation of cement paste has long been recognized as one of the causes of reinforcement corrosion. On the other hand, carbonation causes numerous chemomechanical changes in the cement paste, most notably changes in strength, porosity, pore size distribution, and chemistry....

An experimental and modelling evaluation of the deformation and fracture of quasi-brittle reticulated vitreous carbon foam

In quasibrittle materials the addition of specific microstructural features such as porosity can lead to departure from linear elastic behaviour prior to maximum force, followed by graceful failure. A simple but extreme example is reticulated vitreous carbon foam, with its opencell structure of brittle ligaments connected in a threedimensional...

Cracking of SHCC due to reinforcement corrosion

Reinforcement corrosion is the most important deterioration mechanism affecting reinforced concrete infrastructures. After corrosion starts, expansive pressures are exerted onto the surrounding concrete, causing cracking and spalling of the cover concrete. The amount of cover cracking can possibly be reduced by using strain hardening...

Use of phase change materials (PCMs) to mitigate early age thermal cracking in concrete: Theoretical considerations

Phase change materials (PCMs) have found their use in concrete technology for increasing energy efficiency of building envelopes. In recent years, however, new potential applications for PCMs in concrete have been suggested, for example for reducing freeze-thaw damage and melting of ice forming on top of concrete pavements. A recent application...

Influence of Cracking on Moisture Uptake in Strain-Hardening Cementitious Composites

Strain-hardening cementitious composites (SHCCs) are a class of cement-based materials that show strain-hardening behavior in tension. This is achieved by multiple microcracking, which results in a tightly spaced crack pattern with relatively small crack widths (50–80 μm, in general) and high strain capacity (up to 4–5%). Because of their...

Microscale Testing and Modelling of Cement Paste as Basis for Multi-Scale Modelling

This work aims to provide a method for numerically and experimentally investigating the fracture mechanism of cement paste at the microscale. For this purpose, a new procedure was proposed to prepare micro cement paste cubes (100 × 100 × 100 µm3) and beams with a square cross section of 400 × 400 µm2. By loading the cubes to failure with a...