Can I use mortar or grout instead of concrete to make a concrete pot?

I'm wanting to make a concrete pot and several other sculpture type things. The reason why I don't want to use concrete is cos the particles are too big and make it tricky to pour into my molds. But I don't know if mortar or grout are strong enough to use instead of concrete. I also use some smal mesh in the middle as a kind of reinforcing. Any advice would be much appreciated. Thanks.