ᐅ Incorporating splash guard strips with old concrete debris around the house?

Hello,
I still have a large amount of leftover concrete pieces (medium-sized chunks) from a former wall. Since I don’t want to dispose of them, I thought about incorporating them into the splash protection strip around the house. For better appearance and improved properties, I would then fill the top 10cm (4 inches) with the usual gravel. Would this work?

I would also appreciate any additional advice regarding the splash protection strip. For example, is 80cm (31.5 inches) necessary, or would 60cm (24 inches) depth be sufficient in Berlin (warmer temperatures)? Should a geotextile fabric or something similar be placed at the bottom? Otherwise, I could imagine that the stones might gradually sink into the soil over time due to rain.

I also often hear that a dimpled membrane should be installed against the house. The construction company said that the current building membrane is sufficient. The basement wall build-up consists of 30cm (12 inches) reinforced concrete, bitumen coating, 10cm (4 inches) insulation, and the building membrane, followed by surrounding soil or clay soil.

80cm (31.5 inches) depth for the splash guard strip...?

Ours was maybe 30cm (12 inches)... a geotextile membrane was installed there... then brownish gravel (?) and on top, pebbles...

I find concrete remnants rather questionable... the savings should not be significant:

*** Optional item ***

1. 07 Eaves strip as splash guard, total width = 35cm (14 inches),
with gravel topping and lawn edging stones, gray,
installation on existing subgrade

per linear meter = €19.61 net

The 80 cm (31.5 inches) refers to frost protection. In my splash guard strip, there would also be basement windows that include a small light well. Just because I saved on the depth of the splash guard strip, I don’t want to end up with a flooded basement. The downspouts would also be located within the splash guard strip, and under certain conditions, water could back up and spill out near the downspout. In this case, it would also be advisable to have enough depth in the splash guard strip so the rainwater from the downspout can first collect there. The mentioned clay soil also has a negative impact since water infiltrates very slowly.

However, this is not the main issue; rather, it concerns whether the concrete rubble (allegedly lean concrete) could have any negative effects. I was considering whether the rubble might be too sharp-edged and could cut into the membrane or dimpled membrane, or whether the lean concrete might absorb water or dry more slowly (unlike gravel), potentially causing decay processes and associated odors.

The water should be able to drain away. This would not be guaranteed with rubble.
It does not need to be frost-resistant. 20/30 cm (8/12 inches) is sufficient.
It is a SPLASH guard 😉

Aha, why shouldn’t that be guaranteed with rubble? The rubble does not create a tight seal, and there are likely many cavities in between. So why is drainage not possible?
And yes, I think it should be frost-resistant. Because it is not used solely as a splash guard.