From Waste to Paste: Revolutionary Research one Husk at a Time

Morayo Bakare

John Kevern, associate professor of civil engineering, shares his office with various concrete blocks. The blocks are part of a cement experiment he is conducting with Ph.D. student Mark Bediako.
Kevern and Bediako are currently researching how to effectively combine corn husks, rice husks and plain kernel shells into cement to improve the quality of cement used in Ghana.

“Research began with Mark in 2006 with Pioneer Hybrid,” Kevern said.
Pioneer Hybrid is an international seed company that provides the husks for the experiment. In the US, any research done on vegetation must be done with sponsorship of a company. Use of a seed without company support is illegal. This includes buying a seed from a department store and home-growing it.

Bediako was a student at Kwame Nkrumah University of Science and Technology in Ghana when he met Kevern.
“I met Dr. Kevern at a conference in Las Vegas,” Bediako said. “I was presenting on the use of supplementary cementitious materials used in Ghana. This clay was called pozzolana kaolinitic clay and it was a new material to put into Ghanaian cement.”

Research on cementitious materials is not new for Bediako, who is a research professor in the material engineering division for the Building and Road Research Institute in Ghana.

“If this research is successful,” said Bediako, “we will apply this technology to neighboring countries, such as Nigeria and Togo, as well. In Ghana, where fillers for the cement are lacking, dirt is used as a supplementary material. Its usage reduces the quality of the cement for building homes. However, since work is already being done to solve this issue, incorporating the research will not take too long. There is a lot of waste to be used. Ghana generates 3.4 million tons of waste from various plants per season.”

Cement is the preferred building material and is mixed with other building materials for the walls of homes. The tropical climate of western Africa does not allow for the use of wood, as it heats homes too quickly and is not abundant in Ghana.

Bediako mentions that, in many parts of the US, people can safely sleep outside, which cannot be done in Ghana. He makes this comparison to comment on the level of security needed for a Ghanaian home to protect its inhabitants. Wood breaks and burns easily. For these reasons, it is necessary to research easily accessible, yet adequate filler for cement that will make it stronger and allow Ghana to build sturdier homes to combat its 1.7 million housing unit deficiency.
Corn husks, rice husks and palm kernel shells were the materials selected to supplement the cement because of their abundance in Ghana. After harvest, these are usually left to rot or are burned. Instead of wasting this biomass, however, they can be used to replace about 20 percent of limestone, according to Kevern. There are standards for how much limestone can be replaced, since limestone is one of the main ingredients needed in making cement. Focus has been given to discovering the proper ratio of the biomass materials to limestone so that the cement still retains its quality.

“It’s not as good as portland cement, but it’s good enough for housing,” Kevern said.

Research will end in Oct. when Bediako returns to his home country with the hopes of immediately implementing his work and sharing the technology to other West African countries by this time next year.