Setting curbstones: amount of material for concrete

Hello everyone,

after we moved in October, I would now like to tackle the topic of the outdoor area in the spring.
The area to be paved has already been completely gravelled and compacted by our civil engineer.
We have also already chosen the suitable paving stones and curbstones.

In the first step, just under 100 linear meters of curbstones are to be set as an edging. These will be placed in an approximately 30 cm wide bed consisting of about 10 cm lean concrete + a back support (about 10 cm at a 45° angle).
Now I have calculated the material required:
Required concrete: 100m * 0.3m * 0.15m [length x width x height (simplified calculation for back support)] = 4.5m³ concrete
To mix this, I then need approximately 9 tons of gravel (0/16) and 1.5 tons of cement (60x25kg bags).

Is that correct, or do I have a thinking error somewhere?

Thanks in advance

I guess that should be fine. The volume seems correct at first glance, and the density of concrete is high, so the masses also fit. With concrete, it's easy to make mistakes regarding the masses; for a few point foundations for a climbing tower, I was quickly at 1.5 tons.

Ok, then that seems to fit. Thanks!

Hello, just as feedback in case someone comes across the same question: We have now set about 110 linear meters of deep curbstones and 3 block steps with two elements each measuring 100x35x15cm. About 10 tons of gravel (0/16) and 50 bags of 25kg cement would have been better. Unfortunately, I had to buy extra gravel, cement will be stored for the next project.

The state of the art is lean concrete but not. I would have said 0.1m3/m if I had read it earlier.

how much material do I need for 1 meter of lawn edging (brick 20x10x5.2cm)? I wanted to set it lightly with lean concrete so that moles and the like have a harder time, otherwise I could just use gravel right away