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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

Prof Jonathan Jansen bids farewell to Kovsies
2016-08-31

 

Dear Kovsie staff and students

This is my final message to you all.

I wish to use this opportunity for some brief reflections, share a word of gratitude, and convey a sense of the future for our beloved university.

Since the announcement of my departure, I have had more than a dozen breakfasts with mainly students, but also staff, to offer an opportunity for the final sharing of thoughts and, of course, goodbyes. The most common questions asked at those breakfast sessions were the following, with my responses. I repeat them here, since these might also be of interest or concern to you.

What are your proudest achievements?
Two things. The increase in the academic standard for the UFS, both in terms of admission standards and pass rates, but also in relation to the requirements for appointment and promotion especially of professors. This is important because in a globally competitive world, a university stands or falls by the quality of its degrees. And for this you need the best students and the best professors.

What would you do differently, given another chance?
Nothing. I believe that leadership is about doing the best you can with the cards you are dealt in the circumstances in which you are placed. There is no point in second-guessing past decisions. I have always been ambitious as a leader, knowing that most of my goals would be met, and that some would not. That is normal in large and complex organisations, and so, I do not sit around pondering regrets, only remembering with gratitude the things we could achieve together.

What did you learn?
A lot. I learnt that our students have tremendous capacity for greatness both in their academic pursuits but also in their ability to live, and learn, and love together. I have learnt never to underestimate the capacity of our youth to excel in whatever they do. Sometimes I felt I was more ambitious for our students and staff, than they were for themselves. But I have constantly been surprised by the capacity of young students to rise above bitterness and division, and to make great our campus, country, and continent.

I learnt, again, that the overwhelming majority of our staff and students are good people, respectful of each other, and determined to work together to heal our broken past and build a more just society. And I learnt that it is much more fulfilling to build up than to break down, to embrace than to exclude, and to love than to hate.

Were you frustrated with the pace of transformation?
Sometimes, yes. But fortunately I studied educational organisations all my life, mainly schools and universities. Universities are called institutions for a reason, and on century-old sites like the historic Bloemfontein Campus of the University of the Free State, there are core beliefs, values, and practices deeply ingrained in the culture of the place.

Anyone, therefore, who believes that transformation is easy, has obviously never tried to change an old university. It is difficult. You will get blowback. You will get bad press. You will, sadly, lose the support of some people. Some believe the university is changing too fast while others will tell you it is not changing fast enough. As you press for change, you find the university going two steps forward and one step back; in these circumstances, the solemn duty of the leader is simply to ensure that the overall momentum is always forward.

For such a time as this –
a commemorative journey:
2009-2016 (PDF book)

Description: Prof Jansen commemorative journey2 Tags: Prof Jansen commemorative journey

I therefore budget for disappointment even as I relish the many changes we have experienced together over the past seven years. If you want to obtain an objective sense of the scale of the changes at the UFS, ask those students and staff who were here in 2009, not those who came recently. They will tell you that we have a very different university, even though we all acknowledge that there is still some distance to travel. Our remarkable story of change is told in the recent Transformation Audit of the UFS, chaired by Prof Barney Pityana; that Audit Report will be released after it is read and studied by the University Council at its November meeting.

At an individual level, I learnt that most campus citizens change quickly and others more slowly, and that one has a duty to constantly push for change, but also to be patient about change. And I learnt that the ideal change retains the best of our past even as we embrace a more just and inclusive future in which all campus citizens feel that the university truly belongs to each and every one of them.

Are you optimistic about the future of our university?

Yes. The UFS is a very well-managed university thanks to the exceptional talent in the management of our finances, human resources and information technology environments. By the end of 2016, we will have record enrolments, from undergraduates to doctoral students, which is good for our future income. We run a tight ship with regard to the university’s finances, and we have greatly improved the academic standard of our qualifications; in this regard, I am very proud of my senior management team, and the talented middle management personnel, and those who make things work at the coalface of our operations.

I am very concerned, however, about future funding of the 26 public universities and the extremely vulnerable situation of at least 10 higher-education institutions. The economy is not growing and the costs of running a modern university are escalating. The delays in government commission reports on tuition fees do not help, and there seems no urgency ‘higher up’ to make the tough decisions.

We have to ensure free education for the poorest students — that is the position of your senior management – but we also need to guarantee the financial sustainability of our universities. The task of the UFS leadership, in this period of uncertainty, is to manage those two expectations as best we can. But this cannot happen without your assistance, and I do ask that you provide the new Rector and his or her team with the same understanding and support which I have enjoyed from you.

In conclusion
I am grateful.

To the many hundreds of students who have passed through my office and our home, and who sat in my many lectures and engaged me in your residences – thank you for enriching my sense of life and leadership. I am grateful that Grace and I could support and mentor many of you over the years and see you graduate. I am a better leader because of you.

To the staff of the three campuses – there is no university Rector, I can assure you, who enjoyed more love and support than what you offered me since the day I arrived here. Students come and go, but you have been my foundation year after year, and I thank you for that.

To parents, friends, and followers off-campus, in South Africa and abroad – thank you for hundreds of letters, emails, phone calls, prayers and ‘packages of support’ (from biltong to books). In the most difficult times, you rallied from everywhere with a word of support, often on social media. Know this: your words kept me calm in the storm.

Thank you, everyone.

Goodbye.

Prof Jonathan Jansen
Vice-Chancellor and Rector
University of the Free State

Description: Prof Jansen saying goodbey Tags: Prof Jansen saying goodbey

Prof Jonathan Jansen steps down as UFS Vice-Chancellor and Rector (16 May 2016)

 

 


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