Morphology, topography, crystal structure, chemical composition of civil engineering materials - SEM/FIB/EDX

Civil engineering is a discipline that includes all civil construction techniques, from design and maintenance to the construction, operation and rehabilitation of infrastructure structures such as roads, bridges, canals, dams and buildings... The materials used in this field fall into two broad categories: natural (wood, clay, stone, sand) and manufactured (concrete, bricks, plaster, mineral wool, metals, composites, plastics, etc.).

SEM imaging provides morphological and structural information on the surface of a sample. Coupled with a focused ion beam (FIB), a cross-sectional view of the material is obtained. Equipped with an EDX detector, elemental chemical composition data are acquired.

Scanning Electron Microscopy (SEM) can be used to identify damage in building materials, such as corrosion, structural failure and so on, caused mainly by environmental conditions. The dual-beam FIB-SEM system provides valuable information on the subsurface of materials, enabling 3D visualization of these materials. SEM used in combination with BSE and EDX detectors gives access to details of the chemical composition of concrete mixtures, sand and other granular materials.

SEM is a technique producing high-resolution images of the surface' sample. It is used in many fields, from biology to materials science and microelectronics, and on all types of sample. Even insulating materials can be observed after metallization, in a controlled inert atmosphere or at low voltages (close to kV).

SEM is generally used to study the 3D morphology of a surface or object with nanometric resolution. Elemental chemical composition can also be obtained by X-ray microanalysis.

The principle of this technique is based on the use of an incident electron beam of a few tens of kilovolts scanning the surface of the sample, which then re-emits a whole spectrum of particles and radiation: secondary electrons, backscattered electrons, Auger electrons and X-rays. Detection of the various particles or radiation emitted provides information about the sample: its morphology, topography, crystalline structure, elemental chemical composition (qualitative and semi-quantitative analysis)...

TESCAN ANALYTICS has over 30 years' expertise in the use of SEM/FIB/EDX on all types of materials, whether insulating or conductive... With state-of-the-art instruments, our team of experts works with all industrial sectors.

Image 1: SEM imaging of asbestos fibers

Image 2: SEM imaging of fly ash

Image 3: SEM imaging of cement structure

Image 4: SEM imaging of concrete ettringite

Video 1: 3D SEM/FIB reconstruction of actinolite fibers 

These non-exhaustive examples show that scanning electron microscopy (SEM), with or without FIB and EDX, is an ultra-powerful microscopy tool for the structural and chemical study of materials in civil engineering.

With an excellent depth of field (~ 100 x that of optical microscopy), SEM provides high-resolution images of all materials.

For more applications of SEM analysis or our other analytical techniques and microscopy, click here.

The combination of SEM/EDX and ToF-SIMS techniques facilitates comprehensive analysis of material composition. X-ray tomography enables non-destructive visualization of internal features such as porosity, cracks and phase distribution. In dynamic mode, it is possible to visualize 3D changes in internal structures when they undergo modifications such as loading or liquid absorption.