So we didn't get all the concrete poured today. Though we started our first batch at 8am and finished cleaning our tools around 7pm, we finished 27 bags of cement, or just short one bag short of 40% (we purchased 70 bags of cement).
Each bag of cement Phil broke into two parts (he emptied half into a bucket for easier lifting), each weighing 47 pounds. Here's how to mix cement.
Put six buckets of gravel into the mixer. Add a bucket of water to moisten the gravel. Add the two buckets of cement. (Note to those not intimate with construction: there is no such truck as a cement mixer. Cement is the powder, the glue, that holds sand and gravel together to make concrete. A truck with cement would be pointless. Properly named, you see concrete mixers driving around. I often have to edit children's books on the fly: few authors seem to get this one right.) It will stick well to the gravel, and, once the cement goes in, the horrendously loud noise of tossing gravel immediately dissipates. Then comes four buckets of sand. Mix for a few minutes, add more water from the hose's nozzle if needed, and deliver to the site. Pour off.
If you were counting, that's 13 buckets, raised to the mixer's opening which is about four feet off the ground. Poured in while the mixer is spinning, so the person cannot even rest the bucket on the lip of the mixer.
The lightest of the 13 buckets is the 5 gallons of water, weighing just over 40 pounds. The heaviest was the gravel, which Phil estimated at about 60 pounds. So each of the 27 loads averaged about 650 pounds. Which means, yes, Phil picked up over 350 buckets, hoisted them to shoulder height, and flung the contents into the mixer.
Over 17,500 pounds. Almost nine tons.
I tossed in the first bucket of gravel, before the mixer was spinning. I gasped in disbelief to realize that not only would Phil be doing all the stressful driving over the bridge, but all the hoisting, too. I could fill the buckets, but he would have to lift them.
He backed the tractor over the bridge with the first load of concrete. We had hoped that would work easily: back over, turn, dump, and drive straight out. Alas: with the mixer on the back, the tractor could not make a sharp enough turn to evade the rebar poking up. Forward over the bridge, then turn around. All told: twenty-eight trips back and forth across that bridge.
Our first few loads were slow indeed. While Phil dumped the 13 buckets, I refilled them as fast as I could. He drove down to the site, and I climbed down the ladder to meet him. I held a piece of scrap metal roofing on the outside edge, so when the mixer poured, if it happened to pile up or fling out, it would be contained. (It also protected me somewhat from the spinning concrete, though I did end the day with bits in my ears, on my cheeks, and, of course, on my clothes.)
After dumping, the concrete needed a few things to process it. First, we pounded it with a broom handle-type bar: a butter churning motion, forcing gravel into the sides and bottom of the formwork, trying to ensure that it reached below the rebar supports, down to the ground. The first ten loads or so were quite dry, and they needed some heavy pounding.
The result looked something like a gravel pie: very lumpy.
A 2x4 serves to scree the concrete. Resting the board across the form, we jiggle it back and forth, trying to level the top: adding shovels of concrete as needed, or scooping away excess.
Next comes one of the miracles of concrete. Somehow, by taking a float (a flat metal rectangle with a handle on the top) and applying a little pressure, the gravel sinks below the surface, rendering a clean, flat appearance. How can this be? It is crazy!
Use the 2x4 again to get rid of any more excess. Then float again to make it look pretty.
After it has a chance to dry for a half hour or so, float once more to get rid of water, use an edger tool to create a crisp edge, and brush with a little broom to make the surface more receptive to adherence when the concrete blocks arrive.
When we started, Phil did all this, too. Well, I did the pounding part, and added shovelfuls as needed, but besides holding the metal roofing and filling buckets, my part didn't feel terribly robust.
After Jadon finished listening to Car Talk at 11am, we had done perhaps eight loads in three hours. It felt like good progress, but it wasn't at all fast. Now the beauty of having a helpful son comes in.
Jadon took over the filling of buckets. This was basically his full time job for the next seven hours (minus a half hour where he made sandwiches for all his brothers and himself). He stood in the sun, shoveling buckets of sand and gravel. So faithful, so diligent. No complaining, just doing what needed to be done.
This freed me to do the concrete work. Phil would fill a batch and bring it down, and I would manage it: the pounding, the screeing, the floating.
I found it almost ridiculously fun. Concrete has this amazing, almost viscous property, where it pillows up around the 2x4. Have you ever watched a waterbed move? It's like that. My heart has always leaped at the beautiful bulge of moving water (even while always feeling just a bit disappointed that the actual feel of the bulge always escaped: I could see it, but where I sat remained mostly stationary). Or maybe it's a bit like a water balloon, a water balloon the size of a pillow.
Imagine getting to play with a such a beautiful form, such a magical substance, all day! It was very fun for the first twenty-five bags. I kept wanting to giggle at this funny substance that could absorb rocks and pillow up and harden quickly.
On bag 26, Phil said he almost couldn't even lift the buckets any more. I was tired, and because of the angle of the bridge, Phil couldn't simply dump the concrete where it belonged: he had to dump it where he could and I had to move it where it belonged. That was decidedly less fun, even though he made it moist enough that it ran fairly freely.
By bag 27, the sun had gone down and the enormity of cleaning the tools and making dinner and bathing the boys started to overwhelm me. But I cleaned the various tools, cooked up five pound of hamburger or so, ensured all six of us were bathed, and have tried to walk as little as possible since.
One more day, two more days maybe: no matter how much longer it takes, we're thankful not to be pouring tomorrow. We're wishing we could finish in one more day, but Phil thinks he was about at his limit today. And though we've done 50% of the linear feet of the perimeter, the long side that remains is a third wider than the long side completed (it rests not on claystone but on clay, and thus needs a stronger foundation). Good progress today, though!
The weather was perfect, sunny, breezy, in the upper 60s. I think the coldest we've had has been 39, and I was surprised to notice that, unlike the tomatoes which are still somewhat producing, one of my hibiscus has wilted entirely, and the other ones look unhappy. Their mortality is upon them.
Saturday, October 20, 2012
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Thanks for these amazing reports. This was fascinating. And I'm glad you-all are getting a break tomorrow. I expect Phil and Jadon (and maybe you, too) will be feeling very sore . . . on MONDAY.
ReplyDeleteFun times! We do a lot of mixing and pouring by hand, with our construction projects here in Honduras. This week, however, we'll be pouring the footers for the basement walls of my new house. I'm exited about this one!
ReplyDeleteTrish in Honduras
So, Trish, if you mean "by hand," do you mix with a broom handle in a wheelbarrow? Or do you mix with a drill and paddle attachment in a 5-gallon bucket?
ReplyDeleteBecause what we did was a lot of effort, but we definitely enjoyed the advantage of the PTO and the tractor to convey the concrete.
I don't know how long this would take if it was all lugged with wheelbarrows. (I shudder to think.)
Yay for a basement!
What is this structure going to become?
ReplyDelete