Analysis of inner structure changes of concretes exposed to high temperatures using micro X-ray computed tomography

Abstract

The X-ray Computed Tomography (X-ray CT) represents a progressive non-destructive method of analysing the inner structure of materials. The method was used for monitoring changes in inner structure of concrete samples of different composition before and after their exposure to various thermal loads. Eight types of concrete samples were prepared which differed by cement and aggregate types. We intentionally used such composition of concrete mixtures which increased their resistance to high temperatures. The inner structure of samples was analysed using the micro X-ray CT before the thermal loading and after exposure of samples to temperatures of 600 °C or 900 °C. Damages and character of changes in the inner structure caused by high temperatures were influenced by the character of cement and aggregate we used. The analysis of obtained results is presented in the paper.

Behaviour of cement composites with lightweight and heavyweight aggregates at high temperatures

“…Another method is monitoring the presence of cracks inside the concrete using micro X-Ray Computed Tomography. Micro X-Ray Computed Tomography is more exact but requires expensive equipment and is time consuming [38].…”

Estimation of Porosity and Pore Distribution in Hydrated Portland Cement at Elevated Temperatures using Synchrotron Micro Tomography

“…All these techniques are spread across various length scales of concrete. Limited literature is available to understand the thermal effects at different length scales in concrete: heating and recuring effects on microstructure of high strength concrete and hydrated cement are investigated by (Henry et al 2013(Henry et al , 2014; concrete prepared by different binding and aggregates exposed to 600°C and 900°C is the subject of study by (Sitek et al 2015); Alkali activated geo binder and PC based binders from ambient temperature up 650°C are studied by (Rivera et al 2016); mortar microstructure at room temperatures to 1000°C (Kim et al 2012); concrete prepared with mineral admixture 400°C and 600°C is studied by (Su et al 2016).…”

X-Ray CT inspection of subsurface areas of concretes exposed to fast flowing liquids

“…The micro X-Ray Computed Tomography (micro X-Ray CT) method has proven to be a perfect non-destructive laboratory tool for the inspection of subsurface structures. The method enables the analysis of changes of the same sample (Sitek et al, 2015) after exposure to external loadings (mechanical, thermal, chemical, etc.). In this way, some structural states that could be wrongly determined to be caused by a particular loading can be excluded.…”