Thanks 2ndDivisionVet.
KEYWORDS: ancientconcrete; geopolymer; geopolymerization; geopolymers; josephdavidovits; pozzolana; pozzolano; romanconcrete
Posted on 05/28/2016 11:29:45 PM PDT by 2ndDivisionVet
Doesn't sound like science to me. Sounds like Political Correctness searching for grant money.
SLUMP TEST
Roman concrete was so good it didn’t need re-bar in it. That’s good stuff.
Same here - wonder if the show was rigged to make it seem better than advertised.
LOL!!
“If we can replace cement, partially or totally, with some other materials that may be readily and amply available in nature, we can meet our objectives for sustainability,” Buyukozturk says.
Just to be clear: if you fall on concrete hard enough, your bones break, not the concrete.
I’m curious, how does a sealer prevent cracking.
There are many reasons why cement cracks, a poor/wrong mix is one, how it cures, thickness is another, ground heaving, improper soil preparation, rebar placement and there are probably others.
Our ground up here moves a lot during the seasonal changes which is our number one reason for cracking. I knew guy that put zero rebar in a basement. After a year there were 1/2 inch gaps in the basement cracks.
To prevent cracking from ground heaving, a nearby air base runway, they removed the soil 8 feet down and back filled it with a uniform aggregate and compacted to a certain specification, then poured the concrete over it.
Yes, It took us centuries to get back to where the Romans were. Pantheon dome uses heavy aggregates close to the drum, as the section moves up toward the oculus the aggregate gets progressively lighter (volcanic) - genius!
Greeks had them beat as far as beauty though.
now...??....... they are thinking about using nanotech stuff?
i guess we are living at a snails pace , fast !
Here too!
From a video I once saw, towards the top of the dome, they used small ceramic hollow balls as filler in the wall. This served to lighten the mass near the top.
You want the water in concrete to hydrate not evaporate. The sealer locks in the water so it does not evaporate. Thus giving you stronger concrete and less micro voids from evaporation.
That being said too much water will also weaken the concrete. People add more water to make the mix more workable.
Concrete by its nature is strong in compression and weaker in tension. This is why re-bar is added for tensile strength.
Not an expert but many years in construction.
Microscale reinforcing rods? Great... and when the structure needs to be torn down and replaced>.. what then?
didn’t you post something once about ancient concrete being stronger than what we use today?
the article uses the generic term cement when as you have pointed out is Portland cement as opposed to say asphalt cement or epoxy cement
For those journqalists that don’t know the difference between cement and concrete, this article might be quite confusing.
lastly, the term “a random assemblage” is used by the authors when in truth Portland cement concrete for engineering structures is a carefully engineered product for a specific task.
The main ingredients are Portland cement and aggregate of various sizes that include rock (aka stone) and sand. Some would say the rock is aggregate. The size and amounts of the rock and sand particles are designed for the specific purpose of the concrete.
Additionally there are lots of various additives that are included by the engineering design to suit the need.
There are female engineers working on grants at more than MIT making a difference by checking out obsolete concrete formulations
It’s in one or more of those keywords, and it happened more than once if memory serves. :’) I’ve visited most of those topics today, making sure the keywords were in order. :’)
Roman underwater concrete:
http://www.freerepublic.com/focus/chat/1380333/posts
...do as the Romans did:
http://www.freerepublic.com/focus/chat/3027618/posts
This one has a first sentence that will blow your hat right off!
http://www.freerepublic.com/focus/chat/2250645/posts
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