Monday, June 22, 2009

Driveway: Concrete 101

We have a driveway now.
It's pretty spiffy. It will be more spiffy when it cures enough that I feel comfortable driving on it.
{fun fact: concrete takes 28 days to cure to its rated strength}

The next (and last) major step that the builder has left to do is to grade the lot.
Then I can play gardener in the yard.
We'll see how that goes.

This is today right after they came and saw cut the middle line.

Well, I'm going to take this moment to get on my soapbox and provide some education.

Don't worry, not too big of a pet peeve, but I would love it if more people understood the difference between concrete and cement.

So, concrete and cement are two different things, but most people use the words interchangeably.

Cement is an ingredient in concrete. It's the glue that holds all the "stuff" together.

The following is a cross section of concrete from my book about the subject.
{yes, I have read over 300 scintillating pages all about concrete and its additives}
{portland cement association's "Design and Control of Concrete Mixtures", 14th edition, if you're interested :) }

See all the rocks? That's not cement, the cement is some of the gray around the rocks.

Surprisingly enough, cement is actually a relatively small part of concrete, the bulk of it is comprised of gravel, sand, and water. (see below)

Choosing a mix of concrete is a bit like baking.
You choose the ingredients by what you are trying to make.

You can add air entrainment if you are pouring a slab (like a driveway) that is going to be outdoors in a cold climate (like Michigan or Utah). It helps to prevent spalling and cracking during the freeze-thaw cycles.

Or you can add a plasticizer if you are pouring around a whole bunch of rebar, therefore needing it to be more runny. Plasticizer makes it more workable without drastically affecting the strength of the concrete like adding water would.

I could go on and on, but I will refrain as I know this topic is cooler to me than to others.
But thanks for lending an ear.


Ashley Cooper said...

Thanks for teaching me! I was one of those ignorant people who believed they were the same thing. I'll never make that mistake again! :)

Alan said...

Seriously, your blog has not only introduced to my mind the possibility of building a future home, it has pretty much converted me to it.

Carmen said...

Cool beans, such compliments! Thank you much!

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