An analytical equation to predict mortar spalling at laboratory scale

Spalling is the main problem concerning safety in concrete structures under rapid heating. Despite being studied for nearly a century, its prediction remains a challenge. In addition, the main recommendations for its prevention are merely the addition of a fixed amount of polypropylene fibres, without accounting for mix design. This paper...

4D Neutron Imaging of Solute Transport and Fluid Flow in Sandstone Before and After Mineral Precipitation

In many geological systems, the porosity of rock or soil may evolve during mineral precipitation, a process that controls fluid transport properties. Here, we investigate the use of 4D neutron imaging to image flow and transport in Bentheim sandstone core samples before and after in-situ calcium carbonate precipitation. First, we demonstrate...

X-ray micro-tomographic imaging and modelling of saline ice properties in concrete frost salt scaling experiments

Frost salt scaling of concrete is related to cyclic freezing and melting of a few millimeter thick deicer solution on the surface of the concrete. It is almost absent when pure water is freezing and reaches a maximum at a so-called pessimum concentration that for NaCl is around 3%. Different mechanisms have been suggested to explain this...

Fundamental investigation on the frost resistance of mortar with microencapsulated phase change materials

Recent studies have shown that concrete containing Phase Change Materials (PCM) with low transition temperatures may reduce the number of freeze/thaw cycles suffered by the cementitious composite in temperate climates. Nevertheless, the positive influence of such admixtures on the frost resistance of cement-based materials has not been...

Self-healing properties of recycled asphalt mixtures containing metal waste: An approach through microwave radiation heating

The concept of self-healing asphalt mixtures by bitumen temperature increase has been used by researchers to create an asphalt mixture with crack-healing properties by microwave or induction heating. Metals, normally steel wool fibers (SWF), are added to asphalt mixtures prepared with virgin materials to absorb and conduct thermal energy....

Effect of RAP and fibers addition on asphalt mixtures with self-healing properties gained by microwave radiation heating

Microwave heating of asphalt mixtures containing metal fibers is a promising technology for asphalt pavement rehabilitation. The main characteristic of these types of mixtures is that they have the ability to self-heal their cracks when external microwave heating is applied. Prior to this study, the assessment of crack-healing has only been...