Talking about inside knowledge – when last did you look deep into the microstructure of concrete? At the best of times, concrete as we know it has a smooth, grey and even surface. However, when we inspect it a bit more closely under an electronic microscope, things look a little different. Still grey but anything but smooth and even, the products of cement hydration, the calcium silicate hydrate (CSH) crystals, take the shape of needle-like or plate-like compounds growing into each other to form the structure of the hardened cement paste.
The above picture was produced with a scanning electron microscope (SEM), which produces images of a sample by scanning the surface with a focused beam of electrons.
In research and development, SEM is a common technique for understanding concrete on a microscopic level. Understanding the behaviour of cementitious materials during the entire hydration process at a microscopic scale enables us to control flow behaviour of early age concrete, to model the development of mechanical properties, and to understand chemical and physical interactions between the various constituent components in the mix. As a result, we can optimize mix composition and concrete production procedures in line with project requirements and specified performance criteria of the final product. As such, the properties of concrete elements and structures at macroscopic scale are enhanced through our insight into the material’s microscopic particularities. With this picture, we invite you to take a look!