Spectrum Skateparks's blog

Low-Alkaline Shotcrete

Summary
A low-alkaline, high-strength shotcrete was developed by Germany, Italy, and Austria in 1991, it’s better for the environment. It’s now available in North America.

Traditional caustic Shotcrete technology
-Probs with oldschool shotcrete: High-alkaline additives at nozzle creates super caustic dust> skin/lung problems, health hazard. Also crete is porous, lacks strength. Also superfast setting means each layer sprayed on the last, 30% fails to stick, waste and cost. Environmentally, porous so groundwater seeps, caustic alkalines leached out into rivers. Also leachate blocks tunnel drainage.
- Oldschool approach: Gypsum used as setting regulator, keeps concrete workable for several hours.
-Old delilvery: pump shotcrete mix down long pipe.

New Low-Alkaline Shotcrete
Low-alkaline, high-strength shotcrete
High strength, low leachability.
- New Product: Non-alkaline additive instead of gypsum.
- Retards setting for 2-3 minutes for easy spraying and better adhesion, yet allows very rapid hardening.
- No alkaline additives at all.
- Can be premixed with cement instead of added to spraying nozzle.
- Wet aggregate does not trigger setting; only starts when water added at nozzle; can use gravel straight from quarry instead of oven-drying it.
- Crete stays workable for next layer, better adhesion and strength, no wasteful “rebound“.
- Crete denser, less porous.
- Final strength 50% greater than oldschool shotcrete.
- New delivery: New system, load gravel/cement onto hoppers and drive to spraying site.

Development Process
-3 Concrete Co’s (Germany’s Heidelberger Zement (world's fifth largest cement producer)& Italy’s Cementi Buzzi & Austria’s Wietersdorfer und Peggauer)
+ Concrete additives producer (Heidelberger Baustofftechnik)
+ Materials research institute (University of Innsbruck)
= new product
- Developed through BRITE-EURAM funding for unbuilt Ulm/Stuttgart rail tunnels.

Current Status
- New system used successfully on major tunnel projects in Germany and Austria, avail worldwide soon
- New system got 15% of German market in a year.

Commercial Availability
- Heidelberger Zement and Euro/US subsidiaries waiting for approval of patent of technique, will offer worldwide. (Also produced by Cementi Buzzi, soon Wietersdorfer and Peggauer.)
- Conclusion: call Heidelberger Zement, is there a North American distributor yet?
- Circa 1999, this website says “Heidelberger begins North American operation. Heidelberger Zement, parent company of Lehigh Portland Cement, has announced the formation of Heidelberger Calcium Aluminates, a new business that will serve the North American calcium aluminate cement market.“
- So we should ask Lehigh Portland Cement. Should we ask BCRMCA, maybe?
What’s the trade name for this product?
- News flash 01.07.2006 Heidelberger Calcium aluminates website HCA.com says New Company Name
“The HeidelbergCement Group has sold the Heidelberger Calcium Aluminates business line to MEP Mid Europa Partners – a leading independent private equity investment firm focused on Central and Eastern Europe – and the present management.The new group will operate under the name CALUCEM.”
02.07.2007 also on HCA.com: New Website Design New design for www.calucem.com! In the course of our reorganisation we also revised our webdesign. From now on you will find all important information and news about Calucem on this website.
- Check out www.calucem.com

More Information?
Deutsche Umweltstiftung environmental NPO:
- State-approved German environmental NPO, politically independent, volunteer org.
- Goals are nature conservation/ environmental protection. Founded 1982, HQ in Germersheim, motto “Hope through Action”.
-Members mostly scientists and engineers.
- Relevant scientists, judging by description:
- Board of Trustees:
Dr. Rainer Grießhammer, chemist, deputy executive manager of the Öko-Institute (Institute for Applied Ecology), Freiburg
Scientific Advisory Board
Dr. Ulrich Höpfner, chemist, executive manager of the Institute for Energy and Environmental Research, Heidelberg
July 20 emailed them, what about this new concrete, addressed to Griesshammer and Hopfner.

References

“Innovation in Europe”, 1991. E-magazine. http://ec.europa.eu/research/success/en/env/0002e.html

Heidelberger Calcium Aluminates website. HCA.com
http://www.hca.com/content_eng/news/index.html

Calucem website
http://calucem.com

Deutsche Umweltstiftung website.
http://deutscheumweltstiftung.de
Deutsche Umweltstiftung , Postfach 1355, 76713 Germersheim
Tel.: +49(0)7274 / 4767; Fax +49(0)7274 / 77302

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Leftovers
http://cementamericas.com/mag/cement_news_americas_20
This talks about general high-fly-ash concrete, not shotcrete.

We here at Spectrum have been busy researching Photo Catalytic Concrete to help improve build our skateparks Eco-Smart. As concrete is used for many other things besides building skateparks, we thought we should share our research with everyone else out in BuildingGreen land. Enjoy!

Photo-Catalytic Concrete

1. “A Concrete Step toward Cleaner Air” by Bruno Giussani, article on InnoEurope website:

http://innoeurope2.cma.ee/index.php?lang=eng&main_id=16&id=121

- Italian Pavilion in Venice Biennale incorporated this product. Parts of the concrete walls and grounds have been built with cement containing an active agent that, in presence of light, breaks down air pollutants such as carbon monoxide, nitrogen oxide, benzene, and others through a natural chemical process called photo catalysis.

- The technology, called TX Active, has been under development for almost 10 years in the labs of Italcementi, and is starting to be applied commercially to buildings and streets in Italy, France, Belgium, and elsewhere.

- A street in the town of Segrate, near Milan, with an average traffic of 1,000 cars per hour, has been repaved with the compound, "and we have measured a reduction in nitric oxides of around 60%,"

- Active principle in TX Active is a blend of titanium dioxide that acts as a photo catalyser—can be incorporated in cement, mortar, paints, and plaster.

- In the presence of light, speeds up the natural oxidation processes that cause the decomposition of pollutants, transforming them into less harmful compounds such as water, nitrates, or carbon dioxide.

- In Italy, the product is also known as "cemento mangiasmog" or "smog-eating cement".

- It does costs more than typical cement, but active principle only need to be used on the surface.

- "To transform the facade of a five-story building into a photo catalytic surface would add only 100 or so euros ($120) to the cost of a traditional paint or plaster".

- Photo catalytic blocks cost about one-third more than usual paving.

- Used in Richard Meier’s Dives in Misericordia church in Rome (2003), also Air France headquarters inside Charles de Gaulle airport in Paris.

- Architects/ designers like it because it stays white, thus an aesthetic benefit.

2. Photo catalysis Background Info.

http://dev.nsta.org/evwebs/1952/photocatalysis.htm

- Photo catalysis is a reaction which uses light to activate a substance which modifies the rate of a chemical reaction without being involved itself.

- Semiconductors are what are usually used for this.

- Chemically speaking: “…semiconductors are usually selected as photo catalysts, because semiconductors have a narrow gap between the valence and conduction bands. In order for photo catalysis to proceed, the semiconductors need to absorb energy equal to or more than its energy gap. This movement of electrons forms e-/h+ or negatively charged electron/positively charged hole pairs. The hole can oxidize donor molecules…”

- Titanium Dioxide (TiO2) is used because:
-inert
-resists corrosion
-inexpensive
-can react in mild operating conditions
- However, needs UV light for photo catalysis to occur.

3. TX Active - Photo catalytic cement technology.
This is the specific product line, available in North America through Essroc Cement Corp (www.essroc.com)

http://www.essroc.com/default.aspx?pageid=216

TX Active line has 2 products:

1. TX Arca cement, concrete with self-cleaning benefit. Photo catalysis reduces maintenance by destroying most organic/inorganic pollutants that contact concrete and cause discoloration.

2. TX Aria cement, has added ability to mitigate environmental pollution. Effectively destroys airborne pollutants, which are responsible for urban organic pollution.

- How do they work? Products use hydraulic binder with photo catalytic properties.

- Developed over a decade’s R&D by Italcementi’s Technical Research Center in Bergamo, Italy.

- TX Active concrete can be used in vertical, horizontal, structural, architectural pre-cast, plaster and coatings, concrete blocks, jersey barriers, retaining walls, concrete paving and cementitious tiles.

- Photo catalysis also has antibacterial benefits.

4. Concrete That Cleans Air, blog entry on Shawn Hogan fan club blog.

http://www.shawnhogan.com/2006/11/concrete-that-cleans-air.html

- “The results so far are astonishing: A street in the town of Segrate, near Milan, with an average traffic of 1,000 cars per hour, has been repaved with the compound, "and we have measured a reduction in nitric oxides of around 60%," says Italcementi's spokesperson Alberto Ghisalberti. In a test over an 8,000 square meter (or approximately 2 acres) industrial area paved with active blocks near Bergamo, Italcementi's hometown, the reduction was measured at 45%. “
- “In large cities such as Milan, with persistent pollution problems caused by car emissions, smoke from heating systems, and industrial activities, both the company and outside experts estimate that covering 15% of all visible urban surfaces (painting the walls, repaving the roads) with products containing TX Active could abate pollution by up to 50%, depending on the specific atmospheric conditions. „

4. Air-Cleaning Concrete –

http://www.sciencenews.org/articles/20050101/bob9.asp