Doesn't the "cinder" in "cinder block" refer to volcanic cinders from
the Flagstaff, AZ volcanic field originally manufactured and patented by
Harenburg Block Company in the 1960's as a light and stong form of
Concrete Masonry Unit (CMU)? -Mark
Mark Henderson
Ely, NV
James Gibb wrote:
> Fellow HistArchers:
>
> As a one-time mason's helper, I agree with Larry's distinction between
> cement and concrete. The distinction mostly becomes a problem between
> the time the dry cement is mixed with water and the concrete sets up,
> with workers using the terms indiscriminantly. From an archaeological
> perspective, however, that problem is rarely relevant.
>
>
>
> Getting back to a point that I think Larry made in an earlier posting,
> not all block is cinder block. Perhaps manufacturers can afford to be
> casual about the names of their products, but archaeologists cannot:
> cinder blocks include cinders in their matrices, usually visible as
> black bits of slag, coal, or coal ash. These commonly were made near
> sources of such material and, as the use of coal for a variety of
> heating needs has diminished, tend to be earlier than blocks made
> without cinders. The rule is not hard and fast, as coal burning
> continues, although I don't know if cinders, where available, are still
> used in concrete block.
>
>
>
> Jim
>
>
>
> ----- Original Message -----
>
> From: Larry E. Buhr
>
> Sent: Monday, October 01, 2001 2:25 PM
>
> To: [log in to unmask]
>
> Subject: Re: Cinder Blocks & the Auto-Garage
>
>
>
> Larry: I'm going to ask what may seem a stupid question - But I
> bet it's one few archaeologists can satisfactorily answer ,to wit,
> Can you give me a clear and exclusive exclusive distinction between
> the term cement and concrete? I see archaeologists as well as
> builders interchanging the terms constantly. Thanx
> John White
>
>
> Hi John,
>
> This is definitely NOT a stupid question. I nearly included a
> paragraph on this within my long-winded response to the original
> thread, where I tied together various speculations I've been
> considering in regard to the concrete block topic. I agree
> completely that the terms of 'cement' and 'concrete' are confused in
> many situations: even the terms used for the blocks by the
> manufacturers themselves have tended to alternate between 'cement'
> and 'concrete' blocks or bricks, when I believe they are all
> technically of concrete composition once formed.
>
> Within my understanding, cement is the binding, hydraulic or
> water-activated medium (being a dry powder generally composed of
> clay and lime) which along with water is mixed with portions of sand
> and gravel to produce concrete. To produce a mortar, dampened
> cement is mixed with sand only. Cement dampened or mixed with water
> only will set on its own into a very smooth, homogenous product but
> I believe in the interest of lessening expense by extending the
> binder (the cement), and perhaps in terms of improved strength,
> adhesion, or setting properties, sand and gravel portions of varying
> coarseness are nearly always added to make concrete.
>
> In a common instance then, one buys a bag of 'cement' in powdered
> form but when dampened and mixed with extending agents one pours
> 'concrete' into forms or molds, with the final product being then of
> 'concrete' composition.
>
> Hope this helps,
>
> Larry Buhr
> University of Nevada, Reno
>
>
>
>
>
|