Hydrated cement paste constituents observed with Atomic Force and Lateral Force Microscopy

Engineers have frequently used microscopy to better understand the structure of materials. Optical microscopy and scanning electron microscopy have been used for several decades to better understand the microstructure of cementitious composites. Very limited work has been performed to date in the cement area to study the structural characteristics of cementitious materials by Atomic Force Microscopy (AFM). This technical note describes observations from a series of images acquired using AFM as well as Lateral Force Microscopy (LFM). The objective of this work is to better understand how AFM and LFM techniques can be used as tools to better understand the nano and microstructure of cementitious materials. In this work the AFM and LFM techniques could distinguish between CSH particles and crystals of CH on the microscale. The LFM appears to be more sensitive to topographic changes and could more clearly distinguish between the different phases.

► AFM and LFM techniques can be used as a tool to identify cement paste phases.
► CSH particles and crystals of CH could be more clearly distinguish by the LFM.
► CH region had a smoother surface than CSH at large scan range as expected.
► At low scan range both regions exhibited particle nature, with quite different size.
► Larger particles and more bumpy texture were observed for the CSH phase.