Wednesday, October 06, 2010

Pouring Concrete

On Monday evening, my daughter Josephine and I went out to our favorite pizza place, The Flying Squirrel (4920 S. Genesee St., Seattle; 206-721-7620). We go there often because the pizza is outstanding in a city where the pizza has become increasingly outstanding over the past decade, but we went on Monday night specifically to come home with a pizza box.

In fact, so important was this box that I asked for one to be delivered before we placed our order so I wouldn't forget it in my usual post Flying Squirrel pizza state of stupid bliss. When the waiter brought the box, he joked, "Is this part of your strategy to make sure you don't eat the whole pizza?"

I told him no, that we intended to eat the entire pie, the box was going to serve as a mold to for preschoolers to form their own concrete paver, mixing their own cement and water, using real concrete tools. He answered, "That sounds so cool. My 3-year-old nephew loves to do real work projects with me. Are you making more than one paver?" When I told him the plan was eventually to lay pavers along all of our garden paths because of its tendency to get too muddy during the mid-winter months, he went into the back room, returning with a stack of unfolded boxes, declaring, "The Flying Squirrel wants to support your project."

For the first time in my 9 years at Woodland Park my entire Pre-K class is boys. I like to start our days with a science project and this year, given the greater propensity for boys to need full-body learning experiences, my plan is to strive to make the kids sweat as much as possible right from the start. We usually follow science up with "PE" so I'm hoping they're ready for a little sitting and listening as we get into the bulk of our day.

Concrete work, as any of you who have done it know, can be taxing, not to mention the fact we really need to plan for the muddy season. It seemed like the perfect project for a sunny Fall afternoon. We started by gathering our supplies. This is an important first step in working with concrete, you have to work fast, so it's important to have everything ready to go.

The first thing we did was run around the outdoor classroom gathering "treasure" with which to decorate our paver. Each boy was to collect 10 items. Some returned with more, some with less, so there was a lot of running in and out.

Next we had to prepare our pizza box molds.

The lids were removed and the sides reinforced with duct tape. We then used chip brushes to paint the insides with vegetable oil so that the concrete wouldn't stick to the box.

One lesson we learned was that vegetable oil causes duct tape to lose its adhesiveness, at least in the quantities we were using, so we resorted to staples.

Then came the mixing. Cement dust can be toxic if inhaled, so we all donned dust masks and took the project out to the sidewalk in front of the school. The kids stood upwind, several paces off, while I poured the cement into the mixing container, added water, and mixed it until there wasn't much dust left. Then the kids, also wearing gloves to keep the stuff off their skin, got busy mixing.

Once we thought it was good and mixed, we carried everything back into the courtyard. I'd been muttering about how I thought maybe we'd made it too soupy. When we noticed it was already starting to harden, Isak said, "See, Teacher Tom, it's not too soupy."

We filled our molds halfway with concrete, then added some burlap squares for strength and flexibility.

We then finished filling the molds and got to work decorating.

We made two full pavers and had a little left over to make one thin one, which likely won't survive much foot traffic, which will be a future lesson in the potential brittleness of things that we most often think of as strong.

I'd chosen a fast-setting concrete mix. It was impressive to find our pavers already hardened within half an hour.

We're going to give them a week to fully cure, then figure out where to install them.

When we came back inside after nearly 45 minutes of hard work, Lachlan said, "I'm sweating." Mission accomplished.

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michellel said...

If you ever want molds for round stones, the Dollar Tree here in Portland almost always carries plant saucers very cheaply, usually around $4/1 or maybe even less. And reusable :)

Kiera said...

I'm delurking (finally) to say how much I love this project! I grew up on a farm and I remember my dad mixing concrete in his small concrete mixer to patch things or put down flooring for outbuildings. The best part was when he let me help him pour it and smooth it out with the rake. I still love the smell of concrete.

Your blog is pretty much my favorite since I found it. I'm a fellow preschool teacher on hiatus while I finish a degree in Philosophy and Education and raise 2 small kids, but I intend to go right back to preschool teaching as soon as I can. It's the best job I have ever had and it definitely beats teaching college students.

Juliet Robertson said...

Hi Tom

Many thanks for this post - the step-by-step instructions are incredibly helpful along with the photos so I can tell people where to go. In the past I've just slapped cement on top of paving slabs but I like this method and the use of pizza boxes! Hooray.

Best wishes

Scott said...

Who knew that vegetable oil causes duct tape to lose adhesive? I love teaching preschoolers because I learn so much. Thanks for the lesson, Teacher Tom!

(This looks like so much fun...and work!)

Ms. Erin's HeartRoom said...

Oh Tom! We watched workers pour sidewalks at our center and this was something I was tossing around in my head, too. They really want to be able to use a 2x4 to smooth out the sidewalks like the guys did so Ill have to think about forms some more...

Amy A @ Child Central Station said...

Love your pavers! We make stepping stones to add to our rock garden every year. I haven't been brave enough to let the children mix the crete yet. Perhaps next year. Our rock garden has gained a lot of attention because of the great art work our friends have done! I have found that the plastic to-go containers from restaurants work fantastic! We have some round, some octagonal, and some square shapes. The nice thing about the plastic ones is that you can reuse them over and over again. I love the idea of using burlap instead of rebar too..... I will have to experiment with the difference :). Thanks for sharing!

jenny said...

You are my guru.

Anonymous said...

What an amazing real life project. And I think it is so great that you had them wear the masks and gloves even after the dust mixed in. Good for them to see and feel necessary precautions and learn safety at an early age.
So wish we lived in your area so my girl could join the class full of boys!

Saya said...

I love, love, love, LOVE IT!!!!!

Play for Life said...

Nice one Tom! I know a bunch of kinder boys who would enjoy pouring concrete ... boy who am I kidding ...I know a bunch of kinder GIRLS who would also enjoy pouring concrete too!
Donna :) :)

Anonymous said...

WOW, I was just thinking about doing this with my students and for the exact same purpose, song vege garden paths. Thanks for the great idea of using pizza boxes, i was going to make wooden frames but this looks much easier. I was wondering if it would have been easier to mix the cement right in the boxes?
may give it a go.

Unknown said...

Oh my goodness! That looks like so much fun for little kids. I bet they think it's incredible that the weird mud pile turns into cement. That would be such a fun activity for preschool. I'll have to remember this concrete paving activity next time I'm looking for fun activities.

Unknown said...

This looks like a really fun activity for your children to engage in. I know I thought I made a pretty good mark on our house when we were allowed to put our handprints in the wet cement. I still think the prints are at my parents house. It is cool because it became a part of the pavement. They will feel like the house is theirs because they put down some of the pavement.