“Cement” or “Concrete”?

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Mike Hooker writes:

I have a problem with people using the word “cement” when they  mean “concrete”; they are not interchangeable, yet people write and say it all the time.…To clarify, cement is the powder used to make concrete. The hardened surfaces on which we walk and drive are concrete, not cement. It’s really no big deal, just something that leaps out at me when I read it or hear it.

Although many speakers use the words interchangeably to refer to any hard substance, the distinction matters when it comes to putting these materials to use. Fiction writers especially need to know the difference. For example, it would be embarrassing to have a character who is a construction worker mix up the terms.

Cement is a binder.
Concrete is an aggregate that includes cement.

Here are some examples of cement being used where concrete would be the accurate choice:

How to make a nice cement patio

Building a cement patio is no easy chore…

How to Build a Cement Block Patio

The word cement evolved from a word for “small broken stones” to mean “powdered stones.” It entered English from Old French in the 14th century as ciment. The French word came from Latin caementa, “stone chips for making mortar.”

The Romans made their cement by mixing limestone with volcanic ash. They kept this mixture as dry as possible and then pounded it into an arrangement of rocks already in place. They didn’t use rebar, but many of their bridges, aqueducts, and temples still stand.

The most common cement used in the making of modern concrete is Portland cement.

Portland cement was first produced in 1824 by a British stonemason, Joseph Aspdin. He heated a mixture of finely ground limestone and clay in his kitchen stove and then ground the mixture into a powder that hardened with the addition of water. He called it “Portland” cement because of its resemblance to a stone quarried on the Isle of Portland in the English Channel.

The word concrete came into English as an adjective in the late 14th century, from Latin concretus, “condensed, hardened, thick, hard, stiff, curdled, congealed, clotted.” It began as a term of logic, but expanded in meaning until, in 1834, it was being used as a noun meaning “building material made from cement, etc.”

As an adjective, concrete is used as the opposite of abstract.

This, one of many definitions given by the OED, explains why we talk about “concrete nouns”:

concrete: 4. a. Applied by the early logicians and grammarians to a quality viewed (as it is actually found) concreted or adherent to a substance, and so to the word expressing a quality so considered, viz. the adjective, in contradistinction to the quality as mentally abstracted or withdrawn from substance and expressed by an abstract noun: thus white (paper, hat, horse) is the concrete quality or quality in the concrete, whiteness, the abstract quality or quality in the abstract; seven (men, days, etc.) is a concrete number, as opposed to the number 7 in the abstract.

Oxford English Dictionary
Online Etymology Dictionary
“The Riddle of Ancient Roman Concrete,” by David Moore, P.E.

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17 thoughts on ““Cement” or “Concrete”?”

  1. This has been one of my pet peeves for a long time. I’ve worked testing concrete in my job (yes I was the guy who gets to smash concrete cylinders with a compression machine). In the construction industry you are exposed as a newbie or green if you refer to concrete as cement. The only caviot is some old timers still refer to concrete trucks as a cement truck. They’ve put in their time and no one corrects them.

    The other thing is the consistency of concrete is made of 3/4″-1″ stone and is rather thick like a milkshake. It is not like water and takes a couple of hours to setup unless it is quick setting and can harden in less than an hour.

    The less water the harder concrete gets.

  2. Good point about the confusion in usage between “cement” and “concrete”.

    “Concrete” of course can also be used as an adjective meaning “specific” or “definite”, as opposed to “abstract”.
    OED cites “concrete evidence” or “a concrete proposal”.

    Then there’s “concrete poetry” where an unusual typograohic layout is used to enhance the effect on the page.

  3. Primer: Concrete is a building material made of:

    – Portland Cement
    – Course Aggregate (gravel)
    – Fine Aggregate (sand)
    – Water

    – Reinforcement (optional) – some concrete has polyester or fiberglass fibers added to resist random cracking)
    – Admixtures (optional) ( Chemicals/Substances added to change workability , cure time, or other properties depending on what the concrete is being used for )

    Furthermore – Concrete doesn’t “dry” – it actually “hydrates” or “cures” – it’s a chemical reaction between the Portland cement and water that yields a new product (hardened concrete) and heat. Hydrating concrete is exothermic (gives off heat) and the reagents (water, Portland ) must be in exactly the right proportions or the final product will be weaker than it should be

    Concrete is cured wet, usually for 28 days. Letting it “dry” before that is the worst thing you can do for strength. There are compounds that can be sprayed on slabs and other flatwork that slow the evaporation of water and allow it to cure more slowly.

  4. One way we were taught in engineering school to make the distinction is to use a cake simile (admittedly not exact):

    Cement is to concrete like flour is to cake.

  5. Interesting I always thought of abstract as abridge I thought it was a false cognate, ’cause in Spanish “abstracto” is something that is not defined or a form of art not a summary, but now I see you use this word like us.
    I would like someone to clear up something for me please; In Spanish the words curb and sidewalk are interchangeable is it the same in English?

  6. Rod–

    Not in American English. The sidewalk is the paved area you can walk on. The curb is the edge that separates the street from everything that isn’t street. Sometimes the sidewalk lies next to the curb (Street/curb/sidewalk); sometimes there is grass between the curb and the sidewalk (street/curb/grass/sidewalk). One can walk on the curb, of course, but its actual function is to define what is street.

    I think in British English, they use “pavement” rather than “sidewalk,” but I may be completely off base on that one.

  7. If i require 0.01 cubed metres of concrete and am using a 1:2:3 cement:sand:aggregate ratio, how much of each do i need to achieve my required volume?

  8. I’m from New Zealand and I’d never heard people say ‘cement’ for ‘concrete’ back home, but I hear it all the time now that I’m living in America. I think it stands out to me more because the pronunciation is different too – in NZ we say ‘sa-MENT’ and here they say, ‘SEE-ment’. It always irritates me.

    And not that it matters, but in NZ we call it a ‘footpath’ and the curb is just the edge.

  9. Izza, it depends on what part of America you’re in, as to the pronunciation of “cement.” Being originally from California, it’s always pronounced “sa-MENT.” “SEE-ment” is more typical of the South, or regions near it.

  10. While I know there’s a difference between cement and concrete, for some reason, I have always had a problem remembering which is which… until I realized that the occur in alphabetical order. Cement precedes concrete alphabetically and you first have cement which you use to make concrete.

  11. My 60 year concrete patio is VERY badly spalled (?) with many small chunks of a quarter inch depth. Is self leveling concrete advisable, and should a bonding agent be used beforehand?
    I intend to brush it hard, followed by a leaf blower, then hose it and when dry I’ll use the leaf blower again before starting the concrete job. Any advice or corrections would be gratefully accepted, as I have NO experience to fall back on. thanks.

  12. Paul Moroney
    You’ve stumbled into a language blog. We just give advice about the meaning of words. You might try searching “self-leveling concrete.” Here’s one useful looking site that came up when I did that:

  13. It’s new to my knowledge that cement is actually made of small broken stones that are being powdered in order to use for making mortar. If I were to be a builder, I will make sure that I’ll have all the knowledge in order to build the strongest buildings and houses. And also, I am very keen to experimenting things. I am wondering if using a limestone could be a good alternate for cement in building concrete blocks.

  14. Sam,
    Limestone is an ingredient in cement:
    “Common materials used to manufacture cement include limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore.”

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