Bending-resistant base plate driven over by truck in less than 1 day

Hello,

we are just starting to have our own home built on the neighboring plot by a local developer. Unfortunately, the start is anything but joyful. But first things first:

We are having the earthworks done in-house through a company. The start was April 29.
Our assigned site manager already pressured us about 4 weeks ago because another construction had fallen through or something like that. He wanted to quickly do the foundation slab. Since the earthworks crew kept being pulled away for other jobs, the appointment for the foundation slab never happened.
Now, after the earthworks were properly underway, the site manager started pushing again on May 6 because someone else had dropped out. He wanted to do the fine staking out on May 10 and the foundation slab on May 13. Unfortunately, our earthworks contractor said he could still manage it with some difficulties if the slab was in the way. That apparently was a free ticket for our site manager.
After two days of consideration and consultation with the earthworks company, I told him that we would like to have the earthworks finished before the foundation slab comes. Since we are also planning a carport with a tool shed, I wanted the surveying office to stake everything out at once and also start with the garden hut, which we are doing ourselves. I addressed the site manager several times, saying that I did not want the fine staking out and the foundation slab yet. It was always brushed off and he said everything was fine. The evening before the staking out, I called the surveying office myself and canceled the appointment for May 10, since the site manager showed zero reaction.
Early on May 10, I got a call from the site manager saying that I could not do that. He had already scheduled the workers two weeks ago and ordered everything (why didn’t he tell me that two weeks ago? Very strange...). He had the surveying office come back for the staking out. Unfortunately, they did it again. So I sent an email to the developer that same morning saying that I did not agree to this and found it outrageous how customers are treated. Unfortunately zero reaction to date. Consequently, the foundation slab came on May 13 as planned by the site manager and against my will. I was furious.
Moreover, our construction execution drawing was not finished yet; it only arrived by post on May 11. On Sunday, May 12, we relocated the washing machine, which included a drain. I informed the developer that same day with a request for immediate feedback. Consequently, nothing was signed (and still isn’t). A call to the developer on Monday morning shocked me further. They said relocating the drain was no longer possible. If I hadn’t told the workers on site myself (luckily I was working from home) that the drain had to be different, we would now have the wrong drain in the foundation slab. I couldn’t understand what was going on anymore.

Now comes my question...

The foundation slab (rigid bend, because of poor ground) was poured around 2 pm on the 13th and covered around 3 pm. Late the next morning (around noon), the bricks were already delivered. Since my parents live next door, they were able to observe and photograph. I got a picture via WhatsApp around noon showing the truck with bricks driving on the foundation slab, lowering its support to place the bricks behind(!) the "house." Our earthworks contractor also shook his head and asked why they were driving on the foundation slab. "We always do it like this." I was appalled that the drivers dared to drive a 20-ton truck on the foundation slab that was less than a day old. Is that normal? Aside from the fact that the Ytong blocks were placed on the slab but those areas bear the least weight comparatively.
After work in the evening, I was able to check myself. The formwork of the foundation slab was slightly pressed in and cracked and some slab had crumbled (it’s already been plastered over by the masons and covered up. But there are pictures if anyone wants to see).

Are foundation slabs allowed to be driven on so quickly with such heavy equipment? Our building surveyor tried to calm me down but said she could do nothing and that my photos wouldn’t help her anyway.

I feel like I aged at least 10 years in the past few days. I am totally stunned by how a client is treated already at the start of construction.

Maybe someone can help me with some advice. I am really desperate right now.

Well, it's already rare to be this stupid.
When the concrete has sufficient strength depends on many boundary conditions.
"Normal" concrete with "normal" cement needs 2-5 days at the currently very cold temperatures to reach a definable initial strength.
If the truck was too much for the concrete, you can check that with a straightedge.

Thank you for the hint, but what is a Richtlatte and what do you measure with it? Can you do that alone? Meanwhile, the walls of the ground floor are already standing.

The only ones who say that the concrete can handle that are the people from the developer. Everyone else just shakes their head. It is supposedly fast-setting. Hard after 6 hours, drivable after 10 hours.

Could be, at the neighbor who built with a renowned basement company the basement was also set after 48h. What I don't understand is that your parents saw it and said nothing. PS are you sure it's the builder? You have no legal say until acceptance.

Yes, we are building with a company that is building the house for us. And am I only allowed to report defects in the foundation slab upon acceptance? Does the house then have to be torn down again?

And my parents have no authority to do anything there. What were they supposed to say?
Aside from the fact that an "if, would, could" unfortunately doesn’t help me... but 48 hours is a different ballgame than 20-22 hours.

Purely based on experience from several construction sites, it is by no means unusual to distribute the pallets with the stones on the foundation slab the next day. After all, there is still a fine grading layer under the concrete and a gravel layer beneath that. But driving a truck on it, I haven't heard of that yet; that's new to me. Why a driver would take the risk of damaging the vehicle (a foundation slab would be comparable to a 20cm curb) and then place the stones behind it, from where they have to be dragged back, is beyond me.

Stupid situation, you probably can’t do much about it. The tip with the straightedge is nice, but it is by far not long enough. If anything, take the heights with a laser, but for a real proof of a change, you would also have to know the heights beforehand. When concreting, they don’t work to the millimeter. A foundation slab can easily have a height difference of up to 2cm.