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29 November 2022 | Story Leonie Bolleurs | Photo Leonie Bolleurs
UFS green concrete
The Department of Engineering Sciences (EnSci) welcomes collaborations with other departments at the UFS. Pictured here are, from the left: Louis Lagrange, Head of EnSci, Prof Kahilu Kajimo-Shakantu, Head of the Department of Quantity Surveying and Construction Management, Dr Abdolhossein Naghizadeh, and Megan Welman-Purchase, analytical scientist in the Department of Geology.

More than 30 million tonnes of fly ash (residue from coal combustion in power plants) are generated in South Africa annually, with 96% of that being disposed of in landfills. There is thus more than enough of this key ingredient to produce green concrete. 

Green concrete, so called due to its environmentally friendly benefits, is an eco-friendly alternative to conventional concrete based on the Portland cement binder. During the production of green concrete, less carbon dioxide is released into the atmosphere than with the production of ordinary Portland cement (OPC). The latter accounts for up to 8% of all global carbon emissions.

Successful tests

In the Green Concrete Lab, established in 2021 within the Department of Engineering Sciences (EnSci) on the Bloemfontein Campus of the University of the Free State (UFS), Dr Abdolhossein Naghizadeh, Senior Lecturer, researcher, and engineer, is working on green cement and concrete projects.

He uses ‘geopolymer’ technology and a mix of waste materials, alkaline solutions, and recycled aggregates to form concrete mixtures that can provide properties similar to conventional concrete.

Besides being a synthesised inorganic material (not a petrochemical product), the geopolymer cement he introduced has the following properties: it is made from a reaction between aluminosilicate materials and strong alkalis (5-7% of the concrete mixture), it uses water and by-products as raw materials, it does not calcinate lime, thus giving it a low carbon emission, and it is also beneficial from a waste management point of view. 

The waste materials used can include waste from industrial and agricultural sources, such as fly ash, rice husk ash, sugar-cane bagasse, or corncob ash, as well as natural materials such as volcanic ash. In South Africa, sufficient amounts of industrial and agricultural waste are available. 

“So far, we have successfully tested various types of green concrete based on different waste materials,” says Dr Naghizadeh. 

Besides researching the green mixture proportions in the lab, Dr Naghizadeh and his students focused their attention on establishing the strength, durability, workability, and production cost of the product. 

They compared green concrete with conventional concrete. Green concrete’s workability is slightly lower (but he believes that with appropriate mix design it can be corrected), and it has a much higher compressive strength (50-90 MPa), a smaller carbon footprint, and comparable production costs to conventional concrete (depending on the mix design). A very high level of resistance against alkali-silica reaction (concrete cancer) is also present, as well as resistance to carbonation, sulphate attack, and acid attack.
So far, we have successfully tested various types of green concrete based on different waste materials.– Dr Naghizadeh. 

He explains, “The superior durability performance of green concrete is related to its chemical compositions and microstructure. For example, the lack of calcium content in the composition provides better resistance to alkali-silica reaction. At the same time, stronger bonds between elements and polymeric microstructure provide better resistance against acids and fire.”

With all the work and research of the past year and a half, Dr Naghizadeh says they are at the stage where they can prescribe green concrete production recipes for the industry parties based on the specified application and the materials they have.

Biggest accomplishments

“We transferred most of the experimental works to the Green Concrete Lab at the beginning of 2022, which improved our productivity tremendously. Since then, nine journal papers and three peer-reviewed conference papers have been published as outputs of the research projects. Currently, there are also multiple publications under review or in the development stages,” says Dr Naghizadeh.

In addition to him, there are three master's students and one research associate working on their own individual projects.

The department is very proud of its research outputs. Dr Naghizadeh was either author or co-author of all 12 research papers. The focus of these papers was mostly on the formulation of green concrete, based on locally available agricultural waste materials, the formulation of one-part geopolymer cement (when aluminosilicate raw material is replaced with pre-activated aluminosilicate material, water can be used instead of alkali solution), and the development of ambient-cured green concrete (replacing the aluminosilicate raw material with a blend of materials).

Dr Naghizadeh is also the project leader of a group of scientists from local and international universities who are researching sustainable construction materials. These institutions include the Universities of Johannesburg, KwaZulu-Natal, Yaoundé in Cameroon, Erzurum Technical University in Turkey, as well as Nelson Mandela University and the Central University of Technology, which recently came on board. 

 


 


News Archive

SAB World of Learning Brewery bid awarded to Kovsie Brewing
2017-11-28

Description: Kovsie Brewing 2 2017 Tags: Kovsie Brewing 2 2017 

Visitors from SA Breweries (AB InBev), Khosi Mogotsi,
Patience Selesho and Zinhle Ngcobo with
Dr Jan-G Vermeulen and Dr Errol Cason from
Kovsie Brewery.
Photos: Moeketsi Mogotsi

With the recent procurement of SAB by Anheuser-Busch InBev SA/NV (AB InBev), a Belgian transnational beverage and brewing company, the 500L educational brewery located at the SAB Cyril Ramaphosa World of Learning, became available for donation. After an initial shortlisting of three universities, the SAB World of Learning Brewery was awarded to the University of the Free State (UFS) to be managed by Kovsie Brewing.

Prof Corli Witthuhn, Vice-Rector: Research at the UFS, approved the application for a micro-manufacturing liquor licence right in the middle of campus, which effectively put the UFS bid in a class of its own. It is part of her vision that entrepreneurial activities must be visible on campus”

Sixteen universities were approached to obtain the brewery for their respective campuses.

Kovsie Brewing is an initiative started by postgraduate students at the UFS Department of Microbial, Biochemical and Food Biotechnology in 2012. The main objective of this initiative was to expose BSc students to brewing as a practical application of the scientific fields presented at the department.
 

Description: Kovsie Brewing 1 2017 Tags: Kovsie Brewing 1 2017 

Label mock-ups made by
Dr Jan-G Vermeulen from
Kovsie Brewery entered into
the yearly  SAB Intervarsity
Brewing Competition. Kovsie
Brewing has won the best label
competition in 2013, 2014 and 2015
and was placed in the top three in
2016 and 2017.


First brewing and fermentation school
Dr Errol Cason, project leader at Kovsie Brewery, said: “Over the past five years the small-scale experimental brewery has steadily grown to the point where we obtained institutional support to establish the first Brewing and Fermentation School at the university.

Dr Cason explains that the primary role of Kovsie Brewing is to establish an accredited fermentation-based curriculum at the UFS to educate undergraduate and postgraduate students in the scientific process involved in the production of beer. “In addition, the donation enables Kovsie Brewing to provide practical job-related training and skills development on industrial grade equipment,” he said.

Emphasis on entrepreneurship
The secondary role is for Kovsie Brewing to function as a multi-disciplinary platform to stimulate the interaction between students from various fields of study. Currently Kovsie Brewing has well-established cooperative projects with both Marketing and Entrepreneurship programmes.

“In the future, Kovsie Brewing will expand on these multi-disciplinary interactions by incorporating other departments of the UFS with the focus on product development, logistics, as well as the legal aspects concerned with brewing,” Dr Jan-G Vermeulen from the Kovsie Brewery team said.

Corporate social investment representatives from AB InBev recently visited the university. Among others they met Drs Vermeulen and Cason. During their visit they also looked at other university projects, including the Department of Paediatric and Child Health and the Universitas Hospital, the Engineering Sciences Department and the Naval Hill Planetarium.

Khosi Mogotsi from AB InBev said: “It was wonderful to experience the passion with which UFS staff do their work.”

 

 

 

 

 

 

 

 

 

 

 

 

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