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Posts Tagged ‘cast stone’

Fabric formed concrete

Fabric formed concrete


Fabric formwork provides the potential to produce forms that are both structurally efficient and architecturally compelling in a relatively inexpensive and practical manner. By careful shaping of the fabric it is possible to produce complex shapes that would otherwise be too costly to create using traditional formwork.

Chandler describes the work as “a research program that seeks to establish techniques that address complex issues of technical production, risk management and advanced passive energy control, but also accept the legitimate responsibility to be comprehensible and relevant to everyday construction and everyday use. The use of fluid responsive formwork is a technique of constructing which allows the behavior of material to engage with and influence the building process itself.”

During the research, some outcomes were surprising as different fabrics used produce varying textures and finishes on the concrete, some rough, some smooth and everything in-between. Others leave patterns on the concrete that can be reproduced time and time again. The versatility of this formwork is staggering.

Source: International Society of Fabric Forming

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HiTech Lightweight Concrete made of foamed geopolymer

HiTech Lightweight Concrete made of foamed geopolymer


A new range of building products based on a novel form of foamed geopolymer is currently being developed by the CSIRO on behalf of the Company. The geopolymer-based products will add to Hitech Lightweight Concrete’s range of technologically superior building materials.

This geopolymer range of products currently under development delivers lightweight product with significant greenhouse benefits (in contrast to cement-based concrete). The green credentials of this product will position this product range very favourably compared with the high-level greenhouse gas emissions profiles of many current building materials.

Source: Loxley Intertrade.com

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Foamed cement by Allied Foam Tech

Foamed cement by Allied Foam Tech


“Foamed concrete or lightweight concrete derived from Allied’s aqueous foams are suitable for both precast and cast-in-place applications. Some of the highly insulative cementitious foams at densities 48 kg/m3(3 pcf) to 645 kg/m3(40 pcf) or higher can be used as block fills, lightweight roof deck and void-fill materials. Good strength characteristics with reduced weight make lightweight concrete based on Allied’s aqueous foams suitable for structural and semi-structural applications such as lightweight partitions, wall and floor panels, and lightweight blocks. Cementitious foams derived from Allied’s premium systems are suitable for thin layer coating applications where specific performance criteria are required.

Foamed concrete and foamed cement made with Allied’s foam have very fine pore structure, unlike that made with conventional proteinaceous and surfactant foams. The pore structure of Allied’s foams hardly show any sign of deterioration as the density of the foamed cement decreases to below 160 kg/m3 (10 pcf). At densities below 160 kg/m3, the pore texture of foamed cement derived from conventional foam agents becomes so coarse that most of them show severe structural collapse….”

Source: Allied Foam Tech

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No spaces between stones indicates they may have been cast in place with geopolymer.

No spaces between stones indicates they may have been cast in place with geopolymer.


There’s been a lot of interesting discussion on a previous blog post No Spaces Between Stones about building a model to show how ancient structures were made with geopolymer. To my knowledge this would be the first experiment of its kind. LeRoy Martinez, one of our readers, wants to build a small stone to test this theory. LeRoy has a background in mold making and believes he can pull this off using primarily local materials. Some of his comments are pasted below.

“I wish I had known of Davidovitz’s theory before I visited Machu Picchu. I would have certainly spent more time checking the stone texture and fit. I have a mold making background so I can see how some of these could have been cast in place.

Picture this: First they made a 4 sided box from wood and made it large enough so a person can get inside of it. There is no top or bottom. Then he covers the inside of the box with clay and he can be as artistic as he wants. He is making the reverse side of the rock. He only has to make the 4 sides of the stone. The bottom can be flat and the top is open. Then he will press decomposed granite or whatever stone they want to reproduce into the clay. When he has finished he climbs out of the box (mold) and laborers can make multiple pours of the decomposed granite and sodium carbonate solution being sure to coat all of the clay substrate that has the granite surface embedded in it. When it has cured the box (mold) is removed and the stone is finished and in place. All that remains to be done is to wash and brush off the clay.

The decomposed granite that was pressed into the soft wet clay has become the outside surface of the stone. It will provide the texture because it is decomposed granite reconstituted.

The mold can then be set on top of that stone and the procedure done all over again. No two stones will be the same because the sculptor is good at his trade and has his reputation at stake.”

You can read the entire discussion (still ongoing) here.

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No one is sure why granite stones in Carnac, France weighing 100-350 tons were cut and placed in such unusual arrangement.

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Tihuanaco is estimated to be over 17,000 years old, perhaps the oldest city in the world. Nearby Puma Punku is a field of ancient stone ruins that defy explanation. The stones have been carved with machine-like precision into interlocking shapes. The stones are granite and diorite. Diorite is the second hardest stone, which means only diamond tipped tools could cut the stone. Some stones weigh over 800 tons. How were they carved and moved into position from 10 miles away?

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Here’s another example of ancient stonework that defies explanation. Ancient man cutting granite with the precision of today’s CNC machines (.002”). Was this done with simple hand tools? However it was done — whether carved stone or cast geopolymer — would be nearly impossible.

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“Göbekli Tepe, is a hilltop sanctuary erected on the highest point of an elongated mountain ridge some 15 km northeast of the town of Şanlıurfa, in southeastern Turkey and 500 miles away from Istanbul, Turkey. It is the most astonishing archaeological discovery in modern times and also thought to be the oldest advanced civilization on Earth.”

Note that no stone cutting tools have been found, and some of the carvings stand in high relief (see 6:25). Was this structure with 15 ton columns made with geopolymer? If so, then they predate the pyramids (which were probably partly made with geopolymer) by thousands of years.

Related:
Evidence of Cast Stone Near the Pyramids
Ancient Stonework
How the Pyramids Were Built

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Abstract
Air pollution control (APC) residues generated from cleaning gaseous emissions at energy from waste plants burning municipal solid waste are classified as hazardous waste and are a significant disposal issue in the UK. APC residues have been combined with glass forming additives and treated using DC plasma technology. This produces an inert glass (APC glass) that has potential to be reused. APC glass has been characterised and used to form geopolymers. Metakaolin and GGBFS geopolymers have also been prepared. The compressive strength, density, water absorption and porosity of APC glass geopolymers were evaluated. Samples were also characterised using XRD, SEM and FTIR. Results show that APC glass geopolymers have excellent mechanical properties compared to other geopolymer materials with high density, low porosity and particularly high compressive strength. This work demonstrated that plasma treated APC residues can be used to form geopolymers with properties suitable for a range of construction applications.

Source: Geopolymers From DC plasma Treated APC Residues, Metakaolin, and GGBFS

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“The term geopolymer was coined nearly three decades back by Davidovits for alumino-silicate polymers formed in alkaline environment. Geopolymers, have emerged as new generation inorganic polymeric materials well suited for numerous engineering applications. The versatility of these materials can be gauged from civil applications such as high strength cement and concrete, quick repair of materials for ancient archeological structures, to war time repair material for runways. Interior of modern aircraft makes use of fire-resistant properties of geopolymer composites. Preparation of permanent molds for metal casting exploits these materials as precursors for monolithic ceramics. While pure materials such as kaolin and metakaolin were traditionally used for geopolymer synthesis, possibility to use waste materials such as fly ash, slags, etc., further adds to their importance from the point of view of resource conservation, environment and economically attractive material. In essence, geopolymer formation or geosynthesis resembles to natural rock formation process. The basic idea of mimicking rock formation is to target properties of natural rocks. The building blocks, namely SiO 4 and AlO 4 tetrahedra, can form wide spectrum of structures through cross linking. This opens up possibilities to tailor the structure for properties required for specific applications ranging from building materials to matrix to host toxic elements for environmental safety.

Geosynthesis or geopolymerisation is science of making artificial rocks at low temperature by chemical reactions between various alumino-silicate oxides and silicates under highly alkaline conditions, yielding polymeric Si–O–Al–O bonds…”

Source: SciTopics.com

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