Concrete Sculpture Reduces Air Pollution

Recent research into cement has produced concretes that actually reduce air pollution by chemically combining with some of those pollutants. These are called photocatalytic cements. On the scale of small sculpture this will not make a difference to the world's air quality, but in Dundee, Scotland, two artists have used the idea in a large outdoor sculpture in their city centre.

The sculpture is in the form of a car draped in a blanket, but the whole concrete form is white. As a conceptual piece, the sculpture is brilliant. It's as if the last car car in the world has been covered to protect it as a museum piece. At the same time it is healing the air, literally, through exposure to light which triggers a photocatalyst in the cement, which in turn decomposes certain toxic substances in the air such as nitrous oxide.

Matthew Dalziel and Louise Scullion are the two artists who designed the sculpture which was commissioned by Dundee City Council. It uses TX Aria cement which was first developed in Italy.

One of the ironies of the sculpture is that cement production itself generates large amounts of CO2, one of our primary greenhouse gases.

More information at:
http://www.buildingtalk.com/news/cac/cac124.html
Photo at:
http://www.buildersmerchantsjournal.net/news/news.asp?id=5738&title=Castle%27s+anti-pollution+cement+appears+in+Dundee

Essroc Cement has brought this material (along with TX Arca cement, which is self cleaning) to North America. Concrete Decor has archived an article here:
http://www.concretedecor.net/All_Access/601/CD601-product_profile.cfm

Small Scale Duplicate Castings

I've recently completed a short series of wall-mounted pins (brooches), playing on the idea that things–jewelery objects in particular–really change when the material changes, even if the form is identical. It's interesting to compare the value we place on precious metals compared to more utilitarian materials. The sets of three pins are based on one original pod-like form made from fusing silver sheet and wire. This is a technique where you are working with the silver in it's "slush phase", the red-heat temperature range where the silver is above a solid, but below a liquid. You can fuse pieces of silver together, scrape texture into the surface, break pieces off, melt wire into the surface. After immersing in acid to remove oxides, the surface is burnished, but a lot of the roughness and spontaneity of the process remains. Here's a picture of one of the sets:

The silver pin is the one in the middle. On the left, I used a black-pigmented cement mixed with stone dust and additives. On the right, I used white Portland cement with stone dust and additives, and after it was set I rubbed in a thin slurry of pigmented cement, which was mostly then rubbed off.

After some research I discovered the ideal molding material. It's a two-part silicone called Knead-a-Mold. (There are other brands as well.) You take equal parts and mix the putty-like substance together with your fingers–it's completely non-toxic and can even be used for food molds–until the colours are blended completely, then push it against and around the object you want to duplicate. I did this with the silver pin, let it set, then cast plaster around that to give the mold support, then took all the components apart. I mixed up the cement and packed it into the empty silicone mold backed by the plaster. I had previously made pin back assemblies which I embedded into the cement before it set.

The concrete pins are dentical in every way to the original silver one, except in the material itself. Every detail of the metal's fused texture is visible. These two-part non-toxic silicones have amazing potential. I mounted the pins onto a matte white acrylic sheet so they could be placed on a wall when not being worn.

Concrete Construction Online is a really useful resource for concrete sculpture, mainly because of their large inventory of articles from back issues of Residential Concrete and Decorative Concrete magazines. The following link is for an article which gives a good overview of several artists' approaches to concrete sculpture. It was originally published in 2006 in Residential Concrete Magazine.

http://www.concreteconstructiononline.com/industry-news.asp?sectionID=715articleID=292505&artnum=1

Several other excellent articles about concrete sculpture are available as PDF downloads, by searching through the "news and articles" link on their menu bar using the word "sculpture." You'll find information about the artists as well as technical information such as mix design and process.

At Ease with the Material

I received an email today, an edited version of which follows:

Dear Mr. Goss,
I have your book and I have been trying to read, research, and experiment as much as I can before I start in my quest of creating sculptures using concrete. During my research I came across an amazing artist named Mike Moran who uses a technique that makes the concrete look like clay (http://www.anewleafgallery.com/Artist-Detail.cfm?ArtistsID=67). There is nothing out there that explains how to get this look on concrete and there is no way that I can get that look experimenting. By any chance do you happen to know how it is done?
Thank you

This is what I replied:

Thank you so much for telling me about this artist. The work is really amazing. But to your questions...

The simplest answer is that this artist has obviously been working in concrete for some time and understands its qualities and limitations. I'm sure you could get the same effects, but it takes time and lots of practice. I wouldn't worry too much about mixes and recipes–the main issue is understanding the qualities of the material. These pieces weren't done in the same way that you would work with clay. The armatures are carefully worked out; there is probably steel mesh wrapped around the steel rods so that the concrete is given support while it is applied. You cannot get these kind of forms in concrete without that steel structure underneath. You can make concrete more clay-like by adding fibers and pozzolans (e.g. metakaolin, as I described in the book), but it never becomes as malleable and sticky as clay. You have to learn to work within those limitations.

If you look at the clay head pieces as an example–
The gallery describes it: "With very expressive features, this large head appears to rise out of the ground or table top. Moran etched, burnished, and stained the concrete to convey the illusion of weathered clay." As the description says, it's trying to look like clay, but that's an illusion. My best guess is that the head was basically made around steel mesh, from a fairly stiff grey sand/cement mix. Then thinner layers of black-dyed mix were applied by hand (you can see the marks of some of his tools). It looks as if he's using a fairly stiff mix and really pushing it hard against the surface. When it's partially set, he may be scraping some of that off, burnishing it with wood or steel tools, or rough sanding it a bit, then adding a slightly different tinted mix. The white Portland cement (or maybe that's even paint?) appears to have been added last.

As I've implied, this works looks easy—just as an experienced clay artist can make working with clay look easy. But it's not. It looks easy because he's had lots of experience understanding the material and is at ease with the material. I think one of the signs of what we call good art is that it appears to be effortless. But it can only be effortless when the materials are mastered.

I wouldn't worry about doing more research into concrete before starting. My advice would be to just start, and keep doing it, working through the failures until you develop this ease. I know you asked a technical question, and in a sense I've answered from another direction, but I hope it helps.

Concrete Transmits Light

LiTriCon has been around for a few years now, but it still sounds like science fiction to those who think of concrete as massive, opaque and heavy. Essentially, LiTraCon is a fine concrete mix with about 4% of its volume taken up with optical glass fibres. What you end up with is translucent concrete, that is, concrete that light and shadows can be transmitted through.

This blog has good summary of what it is and where it's heading:
http://greenlineblog.com/litracon-light-transmitting-concrete/

Of course you don't get complete tramsission of the scene behind the wall, but you do get the play of light and shadow, the shadows of leaves or people walking by. So instead of concrete becoming a visual barier, it's suddenly opened up. The uses in architecture are immediately obvious, but in small-scale work lamps and light surrounds come to mind, and LiTraCon is already making those for sale.
http://www.litracon.hu/

Andreas Bittis in Germany is also making "translucent concrete," so it appears this is a trend.
http://www.andreasbittis.de/
And here's a third one:
http://www.luccon.com/

Little and Lewis

Little and Lewis create concrete sculptures for the garden in bright colours and shapes that are inspired by both plants and classical Greece. Their book, called A Garden Gallery, by George Little and David Lewis and published by Timber Press, is now out of print but you can get it from their web site at http://www.littleandlewis.com/. I already link to them on my Art Concrete web site but saw a recent article and photographs of their work in the online web site of the OCRegister.

Concrete Sculptures in Catalonia

The Guardian website for May 28, 2008, has an article about some life-size and (be warned) x-rated concrete sculptures in Catalonia just north of Barcelona, Spain. You'll also find a small slide show there. Since the 1970's, artist Xicu Cabanyes has been adding to his private sculpture park.
You can also do a search on Flickr for Cabanyes' work:
http://flickr.com/search/?q=Xicu%20Cabanyes&w=all