DRP started using Pinterest to share some of the images that we’ve been collecting while on recent (and some not so recent) projects. Check us out at https://www.pinterest.com/drpcinc/ to see our latest endeavors in concrete petrography.
The image above is an example of how we continue to discover more and more about the capability of the SEM in concrete petrography. This is a combined backscatter and secondary electron image of a coating on a grain of quartz. The blueish-white stuff is the coating and the orange stuff is quartz. The stark contrast in color reflects the difference in the average atomic number of the constituents of the coating and the rock. EDS analysis showed that the coating consists primarily of iron oxide. However, the EDS analysis also showed the coating contains minor amounts of sulfur. As such, this may be problematic for use in concrete.
We like this image because it really shows how a picture can be worth so many thousands of words. We view the role of the concrete petrographer as a guide into the microstructure of cementitious materials and their constituents. This type of image helps us convey effectively the nature and composition of our clients’ materials and sets the stage for us to discuss the potential implications for the performance of their materials.