The material can be sprayed on a styrofoam frame. Photo by George Joch/Argonne
Argonne Creates Affordable Housing
August / September 2006
Volume 4 Number 4
The United Nations estimates there are almost a billion poor people in the world, 750 million of whom live in urban areas without adequate shelter and basic services. But scientists at the Argonne National Laboratory and Casa Grande LLC are developing a promising new technology that may lead to affordable housing throughout the world.
A tough new ceramic material that is almost twice as strong as concrete may be the key to providing high-quality, low-cost housing throughout developing nations. The ceramic is called Grancrete®, which, when sprayed onto a rudimentary styrofoam frame, dries to form a lightweight but durable surface. The resulting house is a major upgrade to the fragile structures in which millions of the world's poorest currently live.
"Originally, Casa Grande was looking for a concrete substitute for American industry, because concrete erodes in acidic conditions, says Casa Grande president Jim Paul. "But as I traveled in Venezuela, I recognized the demand for cheap housing and I thought about how to use our material for that."
The company was still perfecting its concrete substitute but its material, when dry, occasionally cracked. So Paul partnered with researcher Arun Wagh, a staff ceramist in Argonne's energy technology division, to combine their technologies. Together they developed Grancrete, which helped make Wagh the 2006 Inventor of the Year for the Intellectual Property Law Association of Chicago, the oldest IP association in the country.
According to experiments, Grancrete is stronger than concrete, is fire resistant and can withstand both tropical and sub-freezing temperatures, making it ideal for a broad range of geographic locations. It insulates so well that it keeps dwellings in arid regions cool and those in frigid regions warm. Currently, Grancrete is sprayed onto styrofoam walls, to which it adheres and dries. The styrofoam remains in place as an effective insulator, although Wagh suggests simpler walls, such as woven fiber mats, also would work well and further reduce the raw materials required.
Using Grancrete in developing countries also allows for two important criteria, says Wagh. When you build houses in these poor villages, the materials you use should be indigenous, and the labor should be indigenous, he says. "Every village has soil and ash, and the labor and training requirements are so minimal that two local people can build a house in two days."
According to Paul, workers only need two days of training to learn how to control and calibrate the machinery. Casa Grande typically assembles a team of five people who can start in the morning and create a home that residents can move into that evening. The material cures in 15 minutes; concrete can take hours or days to dry.
Grancrete is made from an environmentally friendly mix of locally available chemicals. It's 50 percent sand or sandy soil, 25 percent ash and 25 percent binding material. Binding material is composed of magnesium oxide and potassium phosphate, the latter of which is a biodegradable element in fertilizer. So even if Grancrete were to decompose, Wagh points out, it would revitalize the soil. "For every ton of conventional concrete, you get a ton of greenhouse gases. With one ton of Grancrete, you get one-tenth of the greenhouse gases."
The cost of building a Grancrete home, estimated by Casa Grande at about $6,000 U.S. for labor and materials, is several times less expensive than a home built using conventional building materials. And the homes themselves are more than four simple walls. For less than $10,000 U.S., laborers can produce Grancrete dwellings of 800 sq. ft.; a typical apartment in a city like Mumbai, India, is only 400 sq. ft.
And Wagh believes that the Grancrete housing would be much cheaper in his native India, using indigenous materials. Born in Karnataka, Wagh grew up in a neighborhood where even to this day the homes have walls and ceilings made from knitted mats of palm leaves and the floors are made of dried cow dung. Wagh says if those knitted mats were made from bamboo, instead of the styrofoam used in experiments, the resulting home would be both comfortable and inexpensive.
"Styrofoam is not cheap in India," he said. A test house using this method has been built in India, and scientific tests are now evaluating its efficacy.
"These homes are regularly subjected to hundreds of inches of monsoon rains and cyclone winds and therefore often have to be repaired or even entirely rebuilt, says Wagh. "Obviously such conditions can have a great impact on the health, well-being, and longevity of the children and adults living there." The Grancrete spray-on cement now offers hundreds of millions of people such as these the opportunity to have adequate housing and live longer, healthier lives.
These types of materials could be readily adapted to provide temporary and permanent housing in disaster areas, and have been suggested for use in regions affected by the tsunami disaster in 2004 and the Gulf Coast by last year's hurricanes.
Grancrete is based on a material called Ceramicrete®, which was developed by Wagh at Argonne in 1996 to encase nuclear waste. The versatile Ceramicrete has many different applications, ranging from treatment of hazardous waste to the creation of a variety of consumer products such as construction materials, structural materials requiring high compressive strength, sealants and coatings.
Ceramicrete also has dental and medical applications.
Argonne and Casa Grande have extensively field-tested Grancrete for structural properties, post-application behavior and production costs. Their next step will be to test it for both earthquake and hurricane resistance, after which they will make the product available worldwide. Wagh hopes the United Nations and other international organizations will step forth and subsidize mass-scale production around the world. And while Grancrete might sound too good to be true, Wagh's response is "Believe it. It's not magic. All we're doing is making a better cement."
Wagh holds more than 14 U.S. patents and has additional pending applications on which he is a named inventor. He has a Bachelor of Science degree in Physics from Bombay University in India, a Master of Arts degree in Physics from Temple University in Philadelphia and a Ph.D. in Physics from State University of New York, Buffalo. He has authored more than 120 scientific articles, written a book, Chemically Bonded Phosphate Ceramics, and has won several awards for outstanding achievement, including a 1996 R&D 100 Award, the 2000 Federal Laboratory Consortium Award for Excellence in Technology Transfer, both for the Development of Ceramicrete, and a 2004 R&D 100 Award for Grancrete. Wagh has worked at Argonne National Laboratory since 1990.
Catherine Foster is a communications specialist at Argonne National Laboratory.
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