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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

New challenges for animal science discussed
2006-04-04

Some of the guests attending the congress were from the left Dr Heinz Meissner (honorary president of the South African Society for Animal Science (SASAS) and senior manager at the Animal Production Institute of the Agricultural Research Council), Mr Paul Bevan (President of SASAS) and Prof Magda Fourie (Vice-Rector:  Academic Planning at the UFS).
Photo: Lacea Loader

New challenges for animal science discussed  

The South African Society for Animal Science (SASAS) is presenting its 41st Congress at the University of the Free State’s (UFS) Main Campus in Bloemfontein. 

The congress started yesterday and will run until Thursday 6 April 2006.  The theme is New challenges for the animal science industries.

It is one of the largest congresses in the 45 years since SASAS was founded in 1961.  Among the delegates 12 African countries are represented, with the biggest delegation from Kenya.  Delegates are also from the United States of America, Iran, Turkey, Germany, the Netherlands and Portugal and African countries like Zimbabwe, Mozambique and Botswana.

“Many of our members play an important role in the training of animal scientists at universities.  The congress is specifically industry orientated so that scientists can interact with farmers through the respective producer organisations,” said Prof HO de Waal, Chairperson of the organising committee and lecturer at the UFS Department of Animal, Wildlife and Grassland Sciences.

According to Dr Heinz Meissner, honorary president of SASAS and a senior manager at the Animal Production Institute of the Agricultural Research Council, the National Livestock Strategy (NLS) Plan clarifies the role and responsibility of the livestock sector. 

“Through this strategy we need to focus on enhancing equitable access and participation in livestock agriculture, improve global competitiveness and profitability of the livestock sector and ensure that the ventures implemented do not over utilise our resources,” said Dr Meissner.

In her welcoming address, Prof Magda Fourie, Vice-Rector:  Academic Planning at the UFS highlighted the related challenges that the UFS will be focusing on specifically over the next five years.  “We have identified five strategic clusters that represent broad areas of excellence in research and post-graduate education.  Two of these are food production, quality and safety for Africa and sustainable development,” she said.

“The food safety and security cluster will focus on the production of food in all its varieties within the African context, encompassing the entire value chain – from production to consumption and nutrition related issues.  This would include a strong emphasis on sustainable production systems,” she said.

According to Prof Fourie the rural development cluster will engage in questions around the role of higher education in sustainable development.  “One of the focus areas in this strategic cluster pertains to sustainable livelihoods.  It refers to a way of approaching development that incorporates all aspects of human livelihoods and means by which people obtain them,” she said.

Prof Fourie said that the challenges we are facing such as food production can only be effectively addressed through collaborative efforts.  “That is why it is important that collaboration takes place between different scientific disciplines, researchers, institutions and countries who are confronted with similar difficulties,” she said.

According to Prof de Waal the congress will give key role players a unique opportunity to present a profile of what they perceive an animal scientist should be and state their specific requirement regarding the animal sciences and its applications. 

“In this way we can determine what the industry’s needs are and we can re-align our curriculum to suit these needs,” said Prof de Waal.

During the next two days, various areas of interest will be discussed.  This includes ruminant and monogastric nutrition, animal physiology, beef, dairy, sheep and ostrich breeding and sustainable farming covering the range from commercial to the small-scale farming level.

Media release
Issued by: Lacea Loader
Media Representative
Tel:   (051) 401-2584
Cell:  083 645 2454
E-mail:  loaderl.stg@mail.uovs.ac.za
4 April 2006

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