Hi! So as you may or may not know I do concrete ramps in my free time.

Till now most of them turned out nice and strong! But lately some of them have been coming out visualy gorgeous but after a while making pressure (not much cuz i'm weak af) some of them split ... so yeah ... (Oh! I don't do the pressure test right ahead ... Usually I leave the concrete 3 days in the mold + 3 days out of the mold before sanding it and give it one more week to settle up before testing it. So about 2 weeks since the inicial mix .)

So what have I possibly done wrong?  
Also , summer is coming and I don't know if that affects the way the concrete dries ... I let the ramps drying in a garage so they are kinda protected but should I hidrate de cement or something like that?

Anyway , hope anyone can help me Thanks!
P.S- Cement and concrete for me are kinda the same thing ... what I use is the one with no sand.
Can't find  rockite in here ... not sure about how it's called here ahahah

not quite sure what's causing this, but with rockite or fast setting cement, you will never have to wait that long. it dries rock solid in a few hours!!

I believe that mike puts pieces of rebar inside the klotz blocks to reinforce them. you could try that, with threaded rod or chicken wire/other wire mesh.

  As for finding rockite, it might be possible to buy online, haven't checked yet, but you could also look for "anchoring cement", "patching cement" or "countertop mix".

Very usefull! Thanks!