concrete mixing

Hi, I am making a flat slab (like a paving stone) to sit on top of a BBQ chimney. It will sit on 4 half bricks, 1 at each corner. Therefore the slab needs to be quite strong. I will put rebar inside, but I am a little confused about the mix. Usually, I mix 1:4 cement and ballast. But...

Hi. I have bought a 120L electric cement mixer. I am wanting to make 0.25 cubic meters of concrete (by weight 1-2-4) using all-in ballast and some bags of cement. I'll need about 3 -ish 25Kg bags of cement. Okay, but how do I manage the mixing with my new 120L cement mixer? Of course, I'll...