Cement mix is a fascinating product, used in endless applications around the house. It’s a mystery to many people, because it doesn’t really have a name, and it isn’t very useful in any way that anybody can think of.
Cement mix is just ordinary Portland cement (which is only about 25% cement). Ordinary Portland cement, being a mixture of sand and gravel and clay, has many properties that don’t make much sense. Clay is heavy, but in cement it doesn’t behave as you would expect. It’s light enough to float on water, but binds together with sand and gravel to make a hard solid material. Clay is soft enough to crumble into powder when you try to grind it, but in cement it doesn’t crack at all. And so on.
Few people are aware that Portland cement isn’t actually made of Portland cement at all; it’s made from ordinary gravel and sand. And nobody would be surprised if they found out that the “cement” in concrete isn’t really cement either: there are no chemical changes at all during the mixing process.
Cement mix is a fascinating product. It is used in endless applications around the world, but what it is supposed to be: concrete. And if you ask what concrete is, the answer soon gets frustratingly vague.
Concrete is a material that can be made out of many different ingredients, but the components it can be made out of are “aggregates”. These are substances that can be mixed together, and when they are mixed together they form something solid and hard. Aggregate parts of cement include sand, gravel, limestone, clay, water, and glue (the most important of these ingredients).
In other words: concrete is a material that only exists as a result of combining sand with gravel with limestone with clay with water with some kind of glue. When those materials are put together according to certain rules they make up a solid mass. The rules tell you how to mix them in order to get concrete.
Concrete is therefore a remarkable material: we could not build anything as complex as our civilization without it. It has been built by people for millennia; every building on Earth was constructed from it at some point in history.
Cement mix is not a new invention, but it is new to me. It seems like something I should know about; after all, I am interested in concrete. But I couldn’t find any good information on the web.
I decided to make up my own definition. My definition begins with: what is Cement Mix? Cement mix is a product made from a mixture of cement and aggregate, which consists of small rock particles mixed with water. The mixture solidifies into a dry mass.” In other words, cement mix is a product: it has characteristics (product) that are not found in the raw materials which constitute it (raw material).
Cement mix is the product of a chemical process, and it is fascinating in its own right. But the real reason to use cement mix is that it can be used to make a lot of other things, some of them very useful:
A batch of cement mix can be ground up into mortar, which can then be used as a kind of glue to stick bricks together. The mortar will dry and harden in about three hours. Bricks are made from clay, which is another kind of product also useful for making things. The mortar makes the bricks waterproof, so they can be used outside; in fact you can use bricks as houses.
Cement mix has a strange pedigree. It once had an exotic name, or rather several names: concrete, portland cement, and fly ash. The first two are still in use, but the last has fallen out of fashion.
But all three have something interesting in common. Portland cement is a mixture of clay and other stuff that doesn’t melt. Fly ash is not a thing you would think of as a “material,” exactly; it’s more like a waste product that can be used to make the stuff we call concrete. But the way it gets used is what makes it special.
Portland cement has been around for about 150 years now, with only one major mistake: the Germans were using it wrong. They were adding hard silica sand instead of limestone, and then when they mixed their moldable molten slurry together with water, they got hard glass instead of good cement.
American engineers could see how this was going wrong from the start; they had no difficulty figuring out how to get it right. The Germans did not, and for seventy years their buildings crumbled when the wind blew. Then one day engineers at DuPont invented something called a “hydraulic ram.” Today those rams are everywhere; in fact they are so ubiquitous that on
It’s a building material. Cement is a kind of sand, but instead of being made up of tiny particles, it’s made up of big ones. So in cement you have sand, gravel and chips. The chips harden into concrete.
The mix doesn’t come from the cement company; they only sell the finished product. It’s made from materials that are already on site. It’s not quite a soup; it’s more like a slurry, but more solid and with more strength as well.
Cement mix is a product you can make yourself for about $15 per ton. It’s worth doing it yourself because it takes about half an hour to mix, and your profit may well be greater than the cost of the raw materials—perhaps ten times as much! But if you go to the cement company instead, they will charge you $3 per ton plus another fee for the truckload of gravel. That’s $4 per ton plus an additional haul-off charge of $11 per ton, or $14 per ton just for having your stuff hauled away!
I don’t know where I’m going with this story except to say that in contrast to most marketing stories I’ve read recently there is no attempt at humor here. There is no
The cement mix is a combination of sand and water. It is a high-performance building material, used in many kinds of buildings, but especially in concrete.
Cement has been around for millennia. It was first used in Mesopotamia and Egypt, and was then known to the Greeks and the Romans. Its origins are unclear, but its first widespread use may have been in Roman times, as a mortar for filling holes in walls.