TIL I was overthinking concrete pours for years

I was on a site in Tucson and the foreman told me to just keep the mix wetter than the spec sheet said. We poured a 40-yard slab that set perfectly with zero cracks, while my usual method would have had me fighting it. When do you guys decide to go off-book on material specs?

3 comments

3 Comments

aaron_cooper2mo ago

That's a risky move though, a wetter mix can really mess with the final strength. Maybe you just got lucky with the weather that day.

leep892mo ago

My buddy's deck posts cracked after a year because his crew added too much water to the concrete. They said it poured easier, but the mix was way off. He had to tear out and redo the whole footing.

reesec182mo ago

The spec sheet strength is based on a specific water to cement ratio. Adding water on site just to make it easier to pour does weaken it. The foreman was probably using a superplasticizer, which lets you add water without messing up the ratio. You gotta check what chemicals are in the mix truck.