Scientists See Sweet Deal for Cement
TUESDAY, SEPTEMBER 24, 2013
Waste ash from sugar production may prove to be an environmentally sweet ingredient in one of the world’s most common building materials, new research suggests.
Researchers in Denmark say that cement made with sugar production waste ash is stronger than ordinary cement, due to its ability to help bind water in the cement.
Further, cement produced in this fashion can withstand higher pressure and crumble less, according to scientists at the Niels Bohr Institute at the University of Copenhagen.
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| irodman / Flickr |
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Scientists from the Niels Bohr Insitute at the University of Copenhagen studied samples of cement that included ash orginating from sugar production waste. |
The team published its research findings Sept. 16 in the journal Scientific Reports.
Cement Production
In order to produce cement, chalk and clay are mixed together and heated at high temperatures in a cement kiln, the scientists report in a research announcement.
“The mixture is then crushed into a powder. When the cement powder is mixed with water, a chemical process takes place, which causes the cement mixture to harden,” the researchers noted.
Ordinary cement production uses massive amounts of energy and emits large amounts of carbon dioxide because it needs to be heated to very high temperatures (sometimes as high as 3,600 degrees Fahrenheit).
The process accounts for 5 percent of global CO2 emissions, the team reported.
Cement with Sugar Ash
Cement mixtures in countries where sugar cane is grown, such as Cuba and Brazil, have long featured sugar agricultural waste product.
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| Digfairenough / Wikimedia Commons |
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The researchers say that cement mixtures that use sugar ash are not only stronger, but are better for the environment. Energy is saved and pollution from cement production is reduced, they add. |
The scientist report that once sugar has been extracted from sugar cane, the process yields fiber waste, which is used as fuel for energy production.
Ash in large quantities is left over from the energy production, they note.
Sample Analysis
With this research, the team aimed to investigate the properties of samples of cement mixed with sugar cane ash on a nano-scale and further map the mobility of water in the cement, explained Heloisa Bordallo, a nanophysics researcher at the Niels Bohr Institute.
“The quality and strength of cement is directly related to how much of the water is chemically bonded. The more the water can move around, the worse it is for the strength and durability,” Bordallo said.
The researchers were sent samples from Brazil. Each sample contained varying amounts of ash from the sugar cane production.
Neutron Scattering Tests
The samples were placed in an instrument where they were “bombarded by neutrons” to determine how the water inside the samples moved, according to the team.
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| Niels Bohr Institute |
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The samples were placed in an instrument (pictured) where they were "bombarded by neutrons." The team says that when neutrons hit the water's hydrogen atoms, they interact and neutrons scatter and are picked up by the detectors. |
The team says that when neutrons hit the water's hydrogen atoms, they interact and neutrons scatter and are picked up by the detectors.
The studies showed that the cement mixed with approximately 20 percent ash had “good properties,” the scientists reported.
The water in the cement pores was bound to the ash and moved around less.
“This explains why the ash cement is stronger, can withstand higher pressure and will crumble less,” according to the scientists.
Moreover, the team noted that while ordinary cement is “generally stronger” during the first few months, after a year the ash cement is stronger.
“If you replace 20 percent of the content with ash, you are saving both CO2 emissions and raw materials, as you use 20 percent less by utilizing a waste product like ash,” said Bordallo.
Waste to Profit
Sugar cane ash may not be the only waste product that could potentially result in a profit by the cement industry.
A recent report by Bloomberg describes the latest initiatives utilized by Holcim Ltd., one of the world’s largest producers of cement.
The Switzerland-based company has taken to burning toxic baby dolls, contraband cigarettes, and old sunglasses to heat cement kilns.
Tagged categories: Bio-based materials; Building Envelope; Building materials; Cement; Concrete; Environmentally friendly; Raw materials; Research
