X-ray computed tomography and fractal analysis for the evaluation of segregation resistance, strength response and accelerated corrosion behaviour of self-compacting lightweight concrete

• Fractal characterisation and X-ray CT analysis of self-compacting lightweight concrete are carried out.
• First study to analyse the segregation of concrete by means of 3D X-ray CT accompanied by image analysis.
• Fractal dimension and fracture energy increase with the increase of the complexity of corrosion morphology.
• Inherent void distribution is the dominant factor determining strength performance.

In this study, fractal analysis and 3D X-ray computed tomography accompanied by digital image analysis technique are used for the quantitative evaluation of segregation resistance, static strength and corrosion-induced cracking in normal self-compacting concrete and self-compacting lightweight concrete. From image analysis performed on the vertical sections of the specimens, it was observed that self-compacting lightweight concrete had much higher resistance to segregation and the use of coarse lightweight particles in self-compacting concrete did not contribute to extensive level of anisotropy. The results also indicate that self-compacting lightweight concrete was weaker in compression than normal self-compacting concrete mainly due to less homogeneous internal structure. Finally, it was also shown that self-compacting lightweight concrete had lower susceptibility to corrosion in the early stage of exposure to the chloride environment than normal self-compacting concrete and greater fractal energies were dissipated in self-compacting concrete made with less porous and stiffer conventional aggregates.