Hello!
Two days ago, I cast a small block measuring 17x17x7 cm on the floor in my garage (currently unheated and uninsulated). A wooden pillar will later be mounted on the block to support part of the roof.
This morning, when I removed the formwork, I noticed that it didn't seem to have become very hard; it crumbled quite easily when I pressed on the edges. After some reading here, I realized that the 4-6 degrees it has been in the garage were too low, but that it wasn't a problem, it just takes longer. It has likely been a bit colder but definitely not freezing. I quickly built an enclosure from insulation and set up a heater to keep it warmer.
Now in the evening, I went out to check the block, and it still crumbled easily at the edges.
Is this normal, or did I mess up? The plan is to erect the pillar in 6 days...