Critical aspects of scanning probe microscopy mapping when applied to cement pastes

The scanning probe microscopy (SPM) mapping technique allows the measurement of materials’ mechanical properties without causing plastic deformation and with much higher spatial resolution compared to the nanoindentation technique. In order to better utilise the SPM mapping technique to identify and quantify the microstructure morphology of individual phases in cementitious materials, this study explores several critical aspects related to the experimental protocol and the data processing during SPM measurement for both ordinary Portland cement paste and slag-blended cement paste. Two data-processing methods are proposed to extract the line data and the area data from the mapping images. The effects of the pixel spacing, the surface roughness of the sample and the magnitude of loads on the measured mechanical properties are discussed. The results of this study will help with selection of the proper testing parameters for identifying different phases and quantifying their sizes under a non-destructive testing condition at a much higher resolution.