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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

During 2011: Prestige Scholars Programme (PSP)
2011-12-01

The University has designed the Vice-Chancellor’s Prestige Scholars Programme (PSP) to promote and support the intellectual breadth and depth required of young scholars to pose questions and generate knowledge in their disciplines and hence to occupy the vanguards of contemporary intellectual enquiry. The programme specifically targets members of the academic staff who are near completion, or have newly completed, their doctoral studies.

The goal is to select no more than 100 of the most promising young scholars and to make substantial investments in their development towards becoming full professors. A tailored, intensive programme of support is designated that combines international placement working alongside leading scholars in the discipline of the prestige scholar, with intensive mentorship and support from within the university.

 Description: 2011 PSP_Thuthuka  Tags: 2011 PSP_Thuthuka

Elite young scholars on the Vice-Chancellor’s Prestige Scholars Programme generated R1,2 million in National Research Foundation Thuthuka and Blue Skies funding in 2011 alone. Dr Katinka de Wet in the Department of Sociology was awarded Blue Skies funding for her work on the Hybrid Identity of the HIV/Aids patient. Thuthuka Grant holders Drs Cilliers van den Berg, Olihile Sebolai, Dirk Opperman and Diaan van der Westhuizen work in the fields of German and Afrikaans trauma literature, microbiology, structural and evolutionary biology, and architecture, respectively. This broad disciplinary range typifies the depth and extraordinary range of scholarship present among junior academics at the UFS.


 Description: 2011 PSP_Liza Coetsee Tags: 2011 PSP_Liza Coetsee

Dr Liza Coetsee, a Y2-rated physicist, is the first of the Vice-Chancellor’s elite cohort of Prestige Scholars to submit for National Research Foundation rating. Dr Coetsee works on the latest of the Nanotechnology Surface Science systems housed in our Department of Physics. As Prestige Scholar, Dr Coetsee conducts research on phosphor solar cells. Her aim is to establish a new Phosphor Solar Cell field at the University of the Free State with Proff. Hendrik Swart and Koos Terblans. As a member of the Prestige Scholar Programme, Dr Coetsee will work in collaboration both with colleagues from the Nelson Mandela Metropolitan University and Prof. Eray Aydil from the University of Minnesota and Editor-in-Chief of the Journal of Vacuum Science & Technology.


 Description: 2011 PSP_Olihile Sebolai Tags: 2011 PSP_Olihile Sebolai

Dr Olihile Sebolai is one of the 2 Vice-Chancellor’s elite Prestige Scholars and a microbiologist. In 2011, Dr Sebolai was awarded a Thuthuka Grant for his research on the yeast pathogen Cryptococcus neoformans, the cause of life-threatening Aids-defining illnesses such as meningitis. Dr Sebolai considers how cryptococcal lipids mediate infectious processes leading to illness. An understanding of these cellular processes will offer hope for future drug development to combat the scourge of cryptococcal meningitis, annually causing the death of over half a million people in Sub-Saharan Africa. Dr Sebolai is also interested in mapping the prevalence and distribution pattern of cryptococcal meningitis in the Free State. This, in turn, will assist health authorities to manage current infections and plan appropriately for potential outbreaks. The Prestige Scholars Programme, with the assistance of the National Research Foundation, will afford Dr Sebolai the opportunity to pursue his research in laboratories in the United States and India in 2012 and 2013.


 Description: 2011 PSP_Louis Holtzhausen Tags: 2011 PSP_Louis Holtzhausen

Dr Louis Holtzhausen, member of the Vice-Chancellor’s Prestige Scholars Programme, has been named by the South African Sports Confederation and Olympic Committee (SASCOC) as team doctor for Team South Africa during the All Africa Games, the largest sports event in Africa. National teams from African countries participated in 23 sports events. As an esteemed South African academic in sports medicine Dr Holtzhausens’ participation was an extension of the work already being done under his supervision at the UFS’s Sports Performance Unit. Many of the athletes who prepared at the Unit were also part of the team. Elite athletes’ illness and injury profiles are one of Dr Holtzhausens’ research focus areas. The exposure to this group in competition was of great value in the identification and development of research niche areas.


 Description: 2011 PSP_ Chantel Swart Tags: 2011 PSP_ Chantel Swart

The South African Society for Microbiology awarded Dr Chantel Swart-Pistor, a Prestige Scholar on the Vice-Chancellor’s elite programme, the top prize for her PhD during a recent gala dinner in Cape Town. Dr Swart-Pistor accomplished a breakthrough in the field of nanotechnology with The influence of mitochondrial inhibitors on zoospore and ascospore development. Her supervisor, Prof. Lodewyk Kock and co-supervisors, Dr Carolina Pohl and Prof. Pieter van Wyk, also stressed the important collaboration with Proff. Hendrik Swart (Physics) and Pieter van Wyk (Centre for Microscopy), which made Dr Swart-Pistor’s work possible. She has presented her work in Beijing (Medichem 2011) and Philadelphia (Biotechnology-2011). She has been invited to return to China in 2012.


 Description: 2011 PSP_ Lizette Erasmus Tags: 2011 PSP_ Lizette Erasmus

Dr Lizette Erasmus, scientific chemist and one of the Vice-Chancellor’s Prestige Scholars, has just returned from a three-month-long research visit to Prof. Hans Niemantsverdriet at the Technical University of Eindhoven in The Netherlands and the University of California, Davis. Dr Erasmus specialises in heterogeneous catalysis. Her visit to Prof. Niemantsverdriet, one of the global experts in the field of surface science, served to round of existing research. In California, Dr Erasmus visited her mentor, Prof. Bruce C. Gates, as part of the objectives of the Rector’s programme for the internationalisation of young researchers. Prof. Gates, an expert in catalysis, could contribute to Dr Erasmus’ research on the characterisation of heterogeneous catalysis and catalytic reactions. In exchange, her expertise in organometallic synthesis added value to Prof. Gates’ existing research. Their continued collaboration gave availed them of the opportunity for interdisciplinary interaction between engineering (Prof. Gates’ speciality) and chemistry, and promises to contribute to increased collaboration between the two universities in future.


 Description: 2011 PSP_Dirk Opperman Tags: 2011 PSP_Dirk Opperman

Dr Dirk Opperman, specialist in structural and evolutionary biology and National Research Foundation Thuthuka Grant holder, joined the Vice-Chancellor’s Prestige Scholars Programme after his postdoctoral work at the Max Planck Institute (KOFO) in Germany. Dr Opperman is the recipient of institutional seed funding to establish a protein crystallisation unit, which in turn led to the donation in 2011 of a multi-million Rand X-ray diffractometer¬ from the University of the Western Cape to complement his existing access to international synchrotrons. Dr Opperman is spending part of 2011 at the University of Exeter (UK) to further his research into the three-dimensional structures of specific enzymes and their trajectories of evolution to specific functions.


 Description: 2011 PSP_Abiodun Ogundeji Tags: 2011 PSP_Abiodun Ogundeji

Abiodun Ogundeji is a member of the Vice-Chancellor's Prestige Scholars Programme. Abiodun's work was recently recognised when he and his co-authors received an award for the best contributed paper at the 49th annual conference of the Agricultural Economics Association of South Africa on the topic, Impact of climate change on planning and dealing with flood disasters in South Africa: A case study of Soweto on Sea. The paper was co-authored by Prof. Giel Viljoen from our Department of Agricultural Economics and Herman Booysen, as well as Gawie du T. de Villiers, Research Associates in the Department of Geography. Abiodun is currently conducting invaluable research on the quantification of the economic value of climate change impacts and the benefits and costs of adaptation in South Africa.

 

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