Cement made from sugar processing waste is stronger than regular cement

Saturday, September 21, 2013 by: J. D. Heyes
Tags: cement, sugar processing waste, material strength

(NaturalNews) Practically everyone knows just how tough concrete is, but scientists in Denmark say that they have found a way to make it even stronger.

Researchers from the Niels Bohr Institute in Copenhagen have discovered that cement made with waste ash from sugar production is stronger than cement made in the traditional manner. Research indicates that the ash assists the binding of water to the center so that it becomes stronger and becomes more able to withstand higher pressures while crumbling less.

The researchers, who published their study in the scientific journal Scientific Reports, noted that traditional cement is made of chalk and clay. Those elements are mixed together and heated at a high temperature in a cement kiln, then crushed into a powder. When the cement powder is mixed with water, a chemical reaction takes place, which then causes the cement mixture to harden.

Key: The amount of water chemically bonded

Per the institute:

In some countries where sugar cane is grown, agricultural waste product from sugar production has been added to the cement mixture for many years. Once the sugar has been extracted from the sugar can you are left with a lot of fiber waste, which is used as fuel for energy production. From the energy production you get a lot of ash, which needs to be disposed of. In some countries, like Cuba and Brazil, the ash is added into cement mixtures.

"I have been studying cement using quasi-elastic neutron scattering for several years and researchers from Brazil asked whether I wanted to analyze samples of cement mixed with waste products in the form of sugar cane ash," explained Heloisa Bordallo, who conducts research in nanophysics at the Niels Bohr Institute, which is located at the University of Copenhagen.

"I decided to say yes to the project, which aimed to investigate the properties on a nano-scale and map the mobility of water in the cement. 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," she said.

Bordallo was provided with a number of cement samples from Brazil - samples which contained varying amounts of ash from sugar cane production. She examined the innermost dynamics of the samples at the ISIS facility in the United Kingdom. She says the samples were placed in a device where they were bombarded by neutrons.

When it sets up completely, ash concrete is much stronger

"Using neutron scattering, we can see how the water inside the sample moves. Neutrons are shot into the sample and when neutrons hit the water's hydrogen atoms, they interact and the neutrons scatter and are picked up by the detectors," said Johan Jacobsen, who performed the experiments as part of his thesis for the graduate program in physics at the institute. "We repeat this for several hours and by analyzing the data we can determine how the water inside the sample is moving and also determine its local environment."

Researchers also demonstrated that the cement mixed with about 20 percent ash had favorable properties. "The water 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," the institute said in a press release.

It generally takes about a week for cement to dry and solidify. After a month, 70 percent of the process is completed, but it actually continues on for a number of years. Researchers said ordinary cement is generally stronger the first few months than ash cement, but after a year the ash cement is stronger.

Researchers said the implications of their study could have global commercial applications.

"The cement industry is huge and if they are to adopt a new idea, they need to have proof that it works. Using quasi-elastic neutron scattering we have now studied cement mixed with ash and shown what is happening and why it is stronger," said Bordallo.

Sources:

http://www.nbi.ku.dk

http://ascelibrary.org

http://eece.wustl.edu