I hope you're able to read through this as I really need help from some expertise. I'm in the process of installing an above-ground pool from Poolkungen. Since the pool is 1.5 m high, a supporting casting was needed, which is 0.5 m high and 0.2 meters wide around the pool. The instructions from Poolkungen state the following.
Excerpt from the manual:
"Calculation of material quantity - Ballast (concrete sand/concrete gravel)
pool diameter x 0.2 m (support casting width) x 0.5 m (support casting height).
Example calculation of material quantity Ballast Ø5 m pool (exactly excavated):
5 m x 3.14 x 0.2 (support casting width) x 0.5 (support casting height) = 1.57 m³"
I happen to have the 5-meter model, but I noticed that their calculation is incorrect. When calculating for a cylinder (0.5 m high) with a diameter of 5.4 (including support casting) minus a cylinder of 5 meters (only the pool), the amount of necessary ballast comes to 1.63 cubic meters. Well, not completely wrong, but still. I thought I would order 2 cubic meters of ballast (concrete gravel) with a margin, which was estimated to correspond to about 3 tons.
Anyway, I am mixing everything myself and when I start feeling halfway done with the support casting, I realize - the ballast won't be enough! I continue to cast and when all the concrete gravel is used up, the wall is 40 cm high and not 50 centimeters. I had taken a margin according to the instructions, but in the end, 2 cubic meters of ballast only resulted in about 1.3 cubic meters of concrete.
My first reaction was naturally that the driver must have shorted me. I called and talked to him, but he said the digger who weighed with the scoop had measured 3.2 tons, and he sounded sincere. I started reading online and realized that a possible explanation could be that you end up with less concrete volume than the volume of ballast used. I understand that sand-mixed materials compact when wetted, but at the same time, 1 part of standard cement is added per 3 parts of ballast (according to Poolkungen's recipe), so I thought the cement would compensate for this. So here I need opinions.
Is there any concrete/mixing professional who has experience with this? Could this explain why the concrete gravel wasn't enough, or is it likely that the driver is lying to me?
This also has implications for the question of responsibility. I purchased concrete gravel according to Poolkungen's instructions:
"Calculation of material quantity - Ballast (concrete sand/concrete gravel)
pool diameter x 0.2 m (support casting width) x 0.5 m (support casting height)."
So. No stipulation for any additional factor.
Now, maybe a 40 cm support wall is enough, but if it's not, shouldn't Poolkungen have some responsibility in this if the problem is that the concrete volume is significantly lower than the added ballast volume? You should be able to rely on the instructions, right?
We're quite dismayed right now because we don't know if this needs to be fixed in some way and how best to do it if it does.
