Microcement is blotchy after sanding

Hey everyone! I am currently working on our concrete staircase with Beton Mineral from residence (Schiefergrau). I am initially satisfied with the processing. However, it looks catastrophic after the first sanding. It is completely spotted. I have attached a picture after sanding… Maybe someone can help me or has an idea how to prevent the spots. Best regards

You will certainly not be able to prevent the different color variations after the mechanical processing. BUT! Mineral surfaces should definitely be provided with a surface protection. This could be, for example, a colorless resin-based sealant. I assume that the surface protection can achieve an at least largely visually identical surface appearance. Please keep in mind that cement-bound building materials, including concrete as well as cement screeds, naturally can have different absorption behavior in different areas. This is material-specific. This can also easily result in "cloud-like" shading. If you want to completely exclude this, you probably have to use a pigmented sealant (after prior priming). --------------- Regards: KlaRa

Did you apply two coats? Since you sanded first, this seems to be the result after the first application?

Did you apply it using a stainless steel spatula? What sanding pads are you using?