Mar 24

Translucent Concrete

Light-transmitting concrete

Litracon Wall

Innovators in the concrete industry never cease to surprise us. When we first heard of “translucent concrete” we weren’t quite sure how these two words could go together! After all, concrete conjures images of heavy, solid, rough material that blocks just about everything and especially light. What if concrete could let light through? What if a wall could also turn into a window to the outside?

So what is this light-transmitting concrete?

As in all new concrete products, they use variations from the traditional ingredients. One of the main differences is the use of translucent alternatives, like glass or plastic fragments to replace conventional aggregates and let light through with the use of resins or clear glue as binding agents. Another formula involves mixing white Portland cement with white silica sand and fiber glass or plastic rods as reinforcement. Various methods have been developed and patented as a result. In most cases, a thin layer of concrete is poured manually in a mold, then fiber glass is placed on top and another concrete layer covers it. This method allows light to travel from one side of the block to the other.

Another benefit of this promising material is its ability to greatly increase insulation for buildings in harsh regions. This means that privacy is retained while allowing daylight in.That’s pretty cool for Northern regions of the world that suffer from lack of lighting for half the year!

Who are some of the pioneers?

Dr. Price from the University of Houston is not only looking into making translucent concrete, he wants to make transparent concrete made from recyclable materials that can be poured on site (currently it is only available in pre-cast bricks or panels). His vision is that in the future, cities could glow from within from translucent (and eventually transparent) zones within curving walls. A tall order that would undoubtedly revolutionize the building industry.

Other players that are selling blocks and panels include Impact Lighting Inc, Lucem (in Germany), Litracon (in Hungry), just to mention a few.

Usages for translucent concrete. Imagine the possibilities…

Translucent concrete lamp

Litracube

 

What started as a cool medium mostly used in art exhibits, in museums, was then introduced into furniture items like desks, lamps, park benches, counters and now found its way into building walls and floors.

At the Shanghai World Expo in 2010, the Italian Pavilion featured its first application in buildings. When blocks of translucent concrete were inserted into a wall in various geometric positions, soft natural light was let in during the day and a gentle glow appeared at night. The building was transformed into a soothing living structure where the separation between the inside and the outside had been greatly reduced.

Translucent wall

Lucem LED concrete wall

In 2013, the German company Lucem erected the first led infused concrete wall, with 136 color-changing led panels controlled with DMX technology via internet! With one click, these same color panels can be turned into one large display wall that can be used for communication and advertising. The age of giant billboards make soon be over!

What if sidewalks could be lit at night? This is what they did in Stockholm and pedestrians can see their path by simply looking down.

It could be use to bring natural light in underground buildings like train or subway stations. Think about safety uses, anything that could be lit from below, like speed bumps, emergency signs in case of power outage etc.

What if concrete could conduct electricity? It can and as a result airport runways and drives could automatically eliminate snow and ice as it builds up. That’s just one practical application that would save billions of dollars in cold regions of the world!

Some challenges and much promises

Being such a novelty material, translucent concrete is only available in prefabricated blocks and panels. It may take a few more years for it to be poured on site. This makes its price 4-5 times that of its conventional counterpart. However, translucent blocks can be inserted in wall and still obtain the natural lighting effect.

One experimental case had structural strength issues and with the help of chemical additives the problem was corrected. Most formulas (like the Lozoncze’s concrete block from Hungry) have shown impressive compressive and tensile strength without steel reinforcement. Translucent concrete can in fact be used a structural support!

If you are a hands-on person and want to play with the idea of translucent concrete, check out this diy article on the subject.

Getting major concrete manufacturers, engineers and architects to experiment with translucent concrete will lead to its broader adoption and more amazing applications. The future of concrete is bright and truly promising!

United Equipment Sales

 

If you have any questions about concrete equipment, give us a call.

References:

http://www.impactlab.net/2009/03/07/litracon-see-through-light-transmitting/

http://www.lucem.de/index.php?id=219&L=1

http://www.economist.com/node/779421

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Mar 15

The Art of Vertical Concrete Pumping

Vertical concrete pumping

High rise construction

With the world tallest building (160 floors) completed in 2008 in Dubai (the Burj Dubai Tower)
reaching 1988.19 Ft (606 meters), the high-rise building industry has come a long way. From its humble beginning hand carrying small concrete buckets, to large buckets being lifted by cranes, the ever growing needs of long distance line pumping has pushed concrete pumps manufacturers to reinvent its technology to respond the ever growing new demands.

Some of the challenges:

When the city of Taipei decided to build in 1998 its Taipei 101 Tower/Financial Center (1,667 feet), the project was even more challenging than Dubai because of the known risks of typhoons, high winds and earthquakes. As a result, the building is able to withstand winds up to 133 miles per hour and 7-point earthquakes! This required concrete filled steel mega columns, mega-truss, a truss structure at the core, a Tuned Mass Dumper System and a 800-ton spherical steel ball suspended like a pendulum! Not your average hi-rise engineering design!

The challenge in long-distance pumping isn’t only the pumping but it is the logistics. How much pipe, hose, elbows, thrusts blocks, anchors ? How many guys you need on-site? Who will set up what by when?

When building structures reach over 1900 feet, concrete has to flow and remain longer in the delivery line (anywhere around 35 minutes). This means that the entire content of the pump chamber has to move through with each motion (piston or peristaltic) otherwise any concrete residue can harden, wear out moving parts and cause serious damage.

Projects placing higher concrete volumes require additional planning and design for pump lines. You will need 1.1 pounds of pressure, when using a standard 5-inch standpipe to move concrete one vertical foot. So, if you need to pump 1000 vertical feet, you will need at least 1.1 pounds of pressure. There is nothing better to understand the complexity involved in vertical pumping the projects than see it. So we have compiled a short series of videos showing long-distance concrete pumping on various projects around the world.

Vertical pumping also requires thorough testing of concrete performance at the batching plant, measuring concrete obtain with various pump types, output and the inner pressure of the pipe. In addition core tests and porosity tests were conducted. In the case of the Taipei financial center, a Schwing BP 8000 HDR pump was selected for consistent output and quality of concrete pumped. For the Burj Dubai Tower, 3 Putzmeister 14000 SHP D super high pressure pumps pumped a total of 165,000 m3 of high-strength concrete over a period of 32 months! Now, that’s durability! The frame, hopper, S-transfer tube and bearings have been enhanced to handle the tremendous force.

Tips From the Pros:

As a rule of thumb, the pipe’s diameter should be minimum 3-4 times the size of the largest aggregate size. When pumping concrete against gravity (vertically), a diameter smaller than the usual 125 mm pipeline should be used. It is absolutely necessary to anchor riser pipelines to the structure for the duration of the project. Pipe bends can be secured by casting them through concrete “thrust blocks”.

Be careful and always top the feeder hopper. NEVER let air into the line, especially at the beginning of the pouring job. Hose whipping is the number one cause of injuries and death on the job. When pumping at great heights, this danger is multiplied. To find out how to avoid hose whipping on the job, you can read this article.

Slump loss isn’t usually a common problem when pumping long-distance especially when the aggregate absorption is low. The key is to keep the aggregate wet during the project. This can easily be accomplished in hot regions with sprinklers watering aggregate piles.

New technologies

The country of Saudi Arabia is developing various hi-strength high-rise concrete mixes (Saudi Readymix Concrete) to be used in conjunction with advanced pumping techniques for the exploding construction market in this region of the world. Their high alumina cement content is heat resistant (up to 1500 C), ideal for building in the Middle East.

Schwing-SP1000X

Schwing-SP1000X

At United Equipment Sales, we carry all major pump brands like Schwing, Putzmeister, Reed, Mayco, Olin and more that can handle just about any job size. Below are some examples. Give us a call at (503)283-2105 if you have any questions on pumps, hose and accessories.

See our latest inventory here.

Vertical concrete pumping

Putzmeister TK30

 

 

 

Reed concrete line pump

Reed 4050

concrete line pump

Olin 565 Concrete line pump

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