I’m planning on pouring a monolithic slab with insulation beneath to prevent frost heave of the ground below. It’s a somewhat common technique, there’s just not many folks I can find in Massachusetts with experience.
The contractor that came out first filled the bottom of the forms with a very sandy gravel mix, maybe 60/40 sand/gravel. The gravel was kinda moist, and then water was used to compact it, and then some water got into it when it rained the other day. This is in the layer that, see above, is called "non frost-susceptible fill." On top of this fill goes the vapor barrier, and then the concrete. The moisture under the vapor barrier is between foam insulation and plastic sheets: the moisture is trapped there for life.
I’m a little worried that with all the effort I’m putting in to mitigate my slab breaking in half, that water is going to freeze and break my slab in half. Contractor's already been fired for a myriad of other offenses, but should I go ahead and replace the gravel he's got down with pea gravel?