My old boss in Phoenix insisted on a 5-inch slump for everything, but I switched to a 3-inch slump on flatwork last year.

He said the wetter mix was easier to finish, but I was always fighting bleed water. The stiffer mix sets up cleaner for me now, especially in the heat. What slump do you guys run for driveways?

3 comments

3 Comments

james9953mo agoMost Upvoted

My uncle's crew in Tucson swears by a 3.5-inch slump for their driveway jobs. They say it's the sweet spot for workability without the bleed water.

eva6663mo ago

Yeah, that old-school thinking gets you in trouble. I had the same fight with bleed water on a big pour last summer, it was a mess. Switched to a 4-inch slump and it was a night and day difference, held its shape so much better. Why make it harder on yourself if the stiffer mix finishes cleaner?

mason49920d ago

Well, I have to push back a little here. I get where you're coming from with the bleed water issue, but a 4-inch slump feels like you're swinging too far to the other side. @james995's uncle in Tucson might be onto something with that 3.5-inch number. I've done plenty of pours here in the Midwest where we deal with temperature swings, and a 3-inch slump with a good water reducer has always given me a stiff mix that finishes clean but still works into the forms without fighting me. The trick is getting the water content just right for your specific conditions, not just dropping the slump for a one-size-fits-all fix.