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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

UFS to host one the most prestigious seminars in leadership
2004-09-28

The Business School of the University of the Free State (UFS) will be hosting the Central Region’s screening of the largest global satellite broadcast of the 2004 Living Leadership: Delivering Results the Right Way event.

The event, which will take place on 21 October 2004 from 09:00-16:30 at the Albert Wessels Auditorium on campus, will be up linked from Atlanta, Georgia, USA, and will be broadcasted via satellite to 95 cities in two countries.

“This is a once in a lifetime opportunity for leaders in the Central Region to gain exposure to the pioneers in the international leadership field,” said Prof Helena van Zyl, Director of the UFS’s School of Management.

The global satellite simulcast will bring together a powerful diverse group of the world’s leading business authorities. This includes Mr Donald Trump, chairman of The Trump Organisation; Mr Mikhail Gorbachev, Nobel Peace Prize Winner and former president of the Soviet Union; Mr Jim Collins, speaking on his recent best-seller, Good To Great; Mr Peter Drucker, father of management and author of The Effective Executive; Ms Rosabeth Moss Kanter, professor at Harvard Business School; Mr Ken Blanchard, best-selling author of The One Minute Manager; Mr John C Maxwell, best-selling author of The 21 Irrefutable Laws of Leadership and acclaimed speaker; Mr Russell Simmons, entrepreneur and co-founder of Def Jam Records and Mr Larry Bossidy, co-author of the best-seller, Execution: The Discipline of Getting Things Done.

According to Prof Van Zyl the Living Leadership global satellite broadcast will give attendants exclusive access to the Financial Mail’s Executive Panel. It will also give local executives and renowned leaders the opportunity to share their interpretation of leadership in practical, relevant terms.

Mr Jack Welch’s executive assistant and author of Managing Up, Ms Rosanne Badowski and Ms Caroline Kepcher, an executive vice president to Mr Donald Trump and a lead role on NBC’s hit show, The Apprentice, will join the panel with a special session.

Each of the cutting-edge insights shared by this gathering of world-class leadership authorities will deliver effective benchmarks which teams will use to shape their business outcomes.

The cost is R950,00 per person (group discount is also available) – this includes the receipt of two free issues of the Financial Mail. Tickets are available at Computicket.

For more information on this seminar visit www.livingleadership.co.za or contact Ms Isa Boshoff at 051-4012874 / boshofia.ekw@mail.uovs.ac.za .

Media release
Issued by: Lacea Loader
Media Representative
Tel: (051) 401-2584
Cell: 083 645 2454
E-mail: loaderl.stg@mail.uovs.ac.za
28 September 2004
 

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