DS26

let’s talk CONCRETE(ly)..

Posted in a design education_@Duke by DS26 on 05.28.2010


(CEMENT+WATER)+AGGREGATES

. . . + C H E M I C A L   A D M I X T U R E S  +  R E I N F O R C E M E N T . . .


Simply put, the material rules our world. It can be found everywhere from infrastructure (roads, bridges, tunnels, highways, etc) to buildings, sidewalks, furniture, and more.

Understandably, it is so widely used because of “permanence”. It’s ability to exist, its strength, and to resist wear and tear, all for a really long time.

Don’t take me wrong… we love it. Concrete that is. It can be ‘formed’ at will.

[ formed: cast – in – place by means of wood formwork ]

Why are we discussing it if it’s loved, widely used, and “permanent” ?

Good question !

Concrete is really old, and common place. At one point in time, back before we lost its recipe (after the fall of the Roman Empire) it might have been a ‘Sustainable’ material.

Today, the process of making concrete is everything but sustainable.

Also, we’ll look to see if there are alternatives…

IN HISTORY [ Opus Caementicium ]

Caesarea Maritima, city harbor built by Herod the great (25-13 B.C.) now found in ruins in the mediterranean coast of Israel, is the earliest known use of underwater Roman Concrete technology.

Types of Concrete, as well as preparation methods and instructions, can be found in the “Ten Books of Architecture” by Vitruvious, dating back to 25 B.C.


BASIC COMPOSITION (in summary)

CEMENT:

‘Clinker’ is made by combining limestone and clay, and heating in kiln at 1450 d C. (2642 d F.)

Following, the clinker is ground to powder form. Now clinker, in raw material is a combination of elements such as calcium, silicon, aluminum, oxygen, and iron.

[ So far so good… sustainably. Or so it seams. What about the grinding process ? The equipment required ? or the energy used ?… and furthermore, the energy that is used by the kiln ? ]

WATER:

Water will be the agent to take cement into the process of ‘hydration’.

Depending on water to cement ratio, one can control workability versus strength.

AGGREGATES:

Fine or coarse. Usually sand, crushed stones, and other natural material.

Most of the time recycled aggregates (those from previously demolished material) can be used in mix design, helping preserve those ‘sustainable’ construction methods.

So… they are all natural materials ?… Doesn’t that make it ‘Sustainable’ ?

The answer to that, sadly, is no.

Even though all materials are natural, the processes we use to crush and grind the materials, the energies used in the ‘kilns’, and even all of the oil used for transport, and emissions, actually create one very un-sustainable cycle.


ADDITIONAL ADD-ON(s)

ADMIXTURES:

Additional substances that, combined with the Basic Composition of concrete, will give the material additional desired qualities or specific characteristics.

EXAMPLES of Admixtures:

1. Superplasticizer: increases strength by reducing needed water in mix.

2. Accelerator: reduces time needed for curing.

3. Retarding: increases time needed for curing.

4. Pigment: adds color to concrete.

[ curing: the process of the concrete drying, while gaining strength… must be according to engineered mix design, strength desired, etc. ]

Unlike the basic composition of concrete, now we have seen that artificial additions are made for either looks or characteristics.

This ‘artificiality’ only exacerbates our ‘sustainability’ (lack thereof) problem.

REINFORCEMENT:

Reinforcement is steel, in the form of bars or ties.

Concrete is reinforced because without it the material is weak in ‘tension’. Concrete without reinforcement is good only in ‘compression’.

Reinforcing Steel (or commonly ‘rebar’) is made of carbon steel, carbon as an alloying natural base, but then manufactured into ribbed barks.

And, you guessed it ! … creating ribs cannot be too sustainable.

For a Bigger Picture of the material, and processes related, do refer to bottom of post for the History Channel’s “Modern Marvels – Concrete”

SO… WHAT CAN WE DO ? … AND, WHERE DO WE GO FROM HERE TO MAKE IT MORE ‘SUSTAINABLE’ ?

Listen in to a leader in the forefront of bio-material development. The video will speak for itself…

But, isn’t Rachel Armstrong just speaking of an idea ? a concept ? … she is not showing us anything.

well, that is true, but hold on.. there are other people that are diving into this with some physical evidence.

SO… THERE ARE NEW SCIENCES ?

Correct !

for example, Ginger Krieg Dosier, an assistant architecture professor, received the 2010 Next Generation Design Competition award for the development of a bio-brick.

– Dosier’s act of alchemy was to apply science to design. “There are thousands of examples of microbial mineral precipitation in the scientific literature, but few if any of them have been explored for use in fabrication of construction or design materials”

( excerpt from Metropolis Magazine )

For more on her design / development, you can visit the article for [ Next Generation Design ]

~

Also, let’s listen to someone that’s thought up a natural remedy for concrete…

Bio-Concrete. He poses the possibility of “maintenance and repair in the future”… but

what if we could implement the same natural processes for simply its creation ?

BIOMIMICRY (or Biomimetics):

A new emerging science where natural processes, systems, and materials, are being emulated for the creation of problem solutions.

The one at hand : Architecture and Construction.

If you are interested in learning more about Biomimicry, visit the [ Biomimicry Institute ]

~

~

MODERN MARVELS – CONCRETE part 1

MODERN MARVELS – CONCRETE part 2

MODERN MARVELS – CONCRETE part 3

MODERN MARVELS – CONCRETE part 4

MODERN MARVELS – CONCRETE part 5



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  1. […] you refer to my  ” Let’s talk CONCRETE(ly).. “ post you will see that, there are individuals all around the world working on such technologies. […]


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