Atomic force and lateral force microscopy (AFM and LFM) examinations of cement and cement hydration products

The objective of this work was to better understand how atomic force microscopy (AFM) and lateral force microscopy (LFM) techniques can be used as tools to understand the nanostructure and microstructure of cement and cement hydration products. AFM and LFM techniques were used on mortar samples to distinguish between CSH, CH, and unhydrated cement particles. The LFM technique appears to be more sensitive to topographic changes than conventional AFM and it can more clearly distinguish between the different phases at high magnification (low scan range). AFM could also be used to calculate the roughness of the interfacial transition zone (ITZ) between aggregate and the cement paste at different ages. The rough surface at the interface of the paste and aggregate is generally interpreted as higher porosity. It was found that a reduction in roughness (i.e., porosity) occurred for samples that were cured for a longer time which are consistent with the explanation of porosity.