Archive for April 2009
You are browsing the archives of 2009 April.
You are browsing the archives of 2009 April.
Cement and Concrete Research is soon to publish a paper by Li, who is a professor in material science and engineering at the University of Michigan, that describes a type of concrete that forms many tiny cracks when overloaded instead of a few large ones, leading to a process in which the concrete effectively “heals” itself.
Even after a 3 percent tensile strain, Li’s samples recovered nearly all of its original strength. “We found, to our happy surprise, that when we load it again after it heals, it behaves just like new, with practically the same stiffness and strength,” Li said. “Self-healing of crack damage recovers any stiffness lost when the material was damaged and returns it to its pristine state. The material can be damaged and still remain safe to load.”
Li and his research group have spent more than a decade developing what he calls engineered cement composites. An early version of this ECC is what made the bendable concrete possible. The current version of ECC keeps cracks under 60 micrometers. The cracks, though small, expose small amounts of unhydrated cement in the concrete. When the concrete is subjected to water and carbon dioxide, it forms a tiny calcium carbonate “scar.” Li found in his lab that between one and five wet-dry cycles are needed to reach final level of healing.
This kind of thing is always great stuff, but cost-benefit analyses often deflate some great innovation. Here, the question is whether a signficant extension in the lifespan of something like a concrete highway can offset the premium paid for ECC-enhanced materials that at one point were looking like they would cost three-times as much as traditional concrete. Nevertheless, U-M says it is is pursuing patent protection for the intellectual property, and is seeking commercialization partners to help bring the technology to market.
Li is supposed to be delivering a keynote address on self-healing concrete at the International Conference on Self-Healing Materials in Chicago in June 2009.
In mid-2005, University of Michigan professor Victor Li unveiled a fiber-reinforced bendable concrete. The concrete is made of what Li’s group calls Engineered Cement Composites. The concrete certainly looks like regular concrete, and Li says it is 500 times more resistant to cracking and 40 percent lighter in weight.
In an interview given at that time, Li told the University of Michigan Daily that ECC-built roads might be able to last for 10 years. That kind of life span would be desirable given that Li estimated that ECC concrete might be triple that of traditional concrete.
The secret to ECC is the use of stretchable fibers that are embedded in the concrete. Traditional concrete has tremendous compressive strength but doesn’t do well under tension. In the past, builders have tried to get around this problem using rebar and mesh.
The use of fibers within concrete goes back at least 30 years. Li’s breakthrough is because of the type of polymers his group used.
Later today I will be posting another video and update on this story featuring Li’s latest improvement: Self-healing concrete.
The Obama administration continues to put money where its mouth is regarding energy innovation. And, they are doing it in a way that should prick up the ears of ceramic, glass and other advanced materials researchers and industry leaders.
DOE Secretary Chu today went to Golden to announce the allocation of nearly $200 million in new spending from the American Recovery and Reinvestment act.
The biggest beneficiary is the National Renewable Energy Lab, which is getting $100 million for “facility and infrastructure improvements” alone.
Another $93 million is being set aside for United States wind energy projects. Chu said, “Wind energy will be one of the most important contributors to meeting President Obama’s target of generating 10 percent of our electricity from renewable sources by 2012 . . . The projects funded by this opportunity will advance wind technology so that it can reliably supply a substantial portion of our nation’s electricity. They will also help in creating more new jobs and expanding a clean energy economy.”
Here is a breakdown on the wind energy funding:
|$45 million||Turbine drivetrain R&D and testing||Develop cost effective hardware for utility scale wind turbines with over a 20-year design life|
|$14 million||Advanced materials||Improve turbine blades, towers, and other components; better process controls for lamination, blade finishing, trimming, grind, painting, materials handling and inspection.|
|$24 million||R&D||Funding for three university-industry R&D consortia for advance material design, performance measurements, and analytical models; improve power systems operations, maintenance and repair; and component manufacturing.|
|$10 million||National Wind Technology Center||NREL project to provide support for wind industry, including testing services; installation of two utility-scale turbines for R&D purposes.|
Here is the NREL facilities-improvement breakdown:
|$68 million||Research Support Facility||Goal is to create the nation’s most energy efficient (LEED Platinum) office building at prices competitive with current construction costs and achieve 50% energy use reduction; develop model design process|
|$19.2 million||Renewable Energy and Site Infrastructure||Install solar and potentially geothermal and fuel cells to replace power currently purchased from utilities.|
|$13.5 million||Integrated Biorefinery Research Facility||Develop commercial-scale cellulose-to-ethanol technologies|
These are great things!
With all due respect to Flo Rida, Steven Chu and the DOE are second to none when it comes to making it snow (the green stuff) this year, and he is doing it where they know a lot about snow: Golden Colorado and the National Renewable Energy Lab. Expect something big, not only because the DOE is billing this as a “major announcement on new funding,” but also because the agency notes that “the visit comes as President Obama marks his 100th day in office.”
The funding will be flowing from the American Recovery and Reinvestment Act. It’s unclear if Obama, himself will be there, but Colorado Governor Bill Ritter will be beside Secretary Chu. Look for the details around 12:30 p.m. Eastern Time.
Hey - it’s Video of the Week Day (Wednesday) and Earth Day. What a great excuse for a video festival. The easy thing would have been to go for videos that show the role in ceramics and glass in solar power, solar thermal, fuel cells, piezoelectrics, fusion, ultracapacitors and so on, but I’ve decided to highlight lesser known applications and efforts. Enjoy!
This Thai video demonstrates a mature, low-tech, low-cost water filter system. The filters usually incorporate colloidal silver, either in the clay or painted on, to provide 99.9% filtration and have been in use in Asia, Africa and South America. There is some cultural resistance to these filters because the water tastes “different” than unfiltered water.
FYI - a “bullnose” is the term for the curved edge given to some ceramic tiles used at finished edges. LIFE+ is the European Union’s financial instrument supporting environmental and nature conservation projects.
Ceramic insulation paint!
This video describes efforts in Brazil to cut emissions and use an alternative energy source (rice husks) to power kilns used to fire brick and other ceramic building materials.