Posted By jim1090 on 09/02/2009 2:51 PM
Why you were long on concrete? Hmmm...do you really think that the batch plant mixes up exactly one yard that arrives out of the chute exactly one yard? No way, no how. Very close, within ACI 304 spec, but not exact. Now multiply that by 10 trucks.
You're taking an engineer's mentality and applying it to real life. Rule of thumb, alot better to dump a load you don't need than to find yourself in need of load that won't appear.
Besides batch plant error, you have pump priming, webbing, internal bucks, tie wire, conduit, plumbing, etc. in addition to rebar that you have to take into account. However, while you may get your volume needed calculations, that has very little to do with what flows from the chute. All in all, your pour in my book was a success. I usually have something formed up if I think I'll have some extra. Better on my property than elsewhere. BTW, that 6 yards may have ended up in the driver's diy project. GREAT and completely legitatime fringe benefit of driving.
Thanks for the vote of confidence!
I think it was 6 trucks w/ 10 yds each. If they were each long by a 1/4 yd, that would do it. I suggested the loads maybe were long, but my concrete man said no way, not with this outfit! The BuildBlock numbers account for webs, I believe. And in my case there were no conduits or plumbing inside the blocks. I hope the load got used for something worthwhile, but my concrete man had his doubts. It was a pea gravel, 6 bag, mix with 6" slump. Not the usual mix most everyone uses.
Another note about DIY. Thinking back maybe my project wasn't as DIY as I might like to think! My helper was experienced in rebar placement in major building construction as well as being experienced in house building. My builder, who advised and supported me, along with his crew, did all the roof work and helped with the siding and interior finish. The only part that was truly DIY on my part was the plumbing and wiring, both of which passed inspections without a hitch.