Dear Harsha,

From what I can see on the backscattered electron image, the material seems to be quite homogenous and you can't see any shades of grey, accordingly. In the upper left corner, there seems to be a small metallic (?) particlel that is more heavy and more bright compared to the surrounding material. So, everything is o.k. with your SEM. I don`t know the composition of the cement but you can try to increase magnification and maybe you will see some differences in minerals involved and some variations in colours. You can also try to use 20 kV instead of 15 kV.

All the best,

Elmar

I can prefer an image anaylsis software to quantify areas of the forms after you process the images in the program such as making binary and filtering some pixel size etc. or you can externally modified the colours of the image by using photoshop etc.. You can reach a related software below. **It is free and easy to use

https://imagej.nih.gov/ij/download.html

I processed your image in the software and give as an example. its black area is 7.182%. You can expand or narrow the areas and then you can quantify in the software. or you paint the your focused minerals on image and then process.

If you have an EDAX facility along with SEM it will be much more useful in identifying the minerals. The intensity of backscattering is a function of the mineral's density and atomic number. For an anhydrous cement sample density and atomic number of the constituent minerals doesn't vary significantly. However you can see a clear distinction in BSE when you look at a hydrated sample. This is the reason why BSE imaging has been primarily used for distinguishing clinker and hydrated phases and not the mineral constituents in the clinker itself. Plus it would work much better in a resin impregnated polished sample. However I am not 100% sure whether it can be used for distinguishing mineral phases in clinker also. You can try and see if you come up with something.

Generally, if you want to know mineral compositions in sample accurately, you should do XRD measurement  first to identifiy mineral phases, rather than SEM +BES/ EDS, that means XRD is the first choice because XRD can give diffractive pattern of  a mineral which reflects the crystal strucuture of mineral, and for most minerals, everyone has its own diffractive patteren which is different from others. However, SEM+EDS/BES just give the information of  micromorphology and chemical compositions, if you identify mineral phases  just  according to these characters, sometimes you will make mistakes. Therefore, I suggest you do XRD test first. 

Xiang

 thanks every one for.your valuable feedback, I am attaching a file which tells us the way to prepare a sample for SEM for cement materials. Hope it is helpful. I appreciate your feedback very much.

Imaging from secondary electrons in SEM is good to study the topography of the sample or the morphology of particles. If you want to reveal the chemical contrast in the cement grains using backscattered images, you need to use polished surfaces, so to eliminate the topographic features.   Sprinkle some cement powder on resin, mix thoroughly, let it set, then grind and polish to see the phases in the cement in BSE mode.