Latest News Archive

Please select Category, Year, and then Month to display items
Previous Archive
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

Media: ANC can learn a lesson from Moshoeshoe
2006-05-20


27/05/2006 20:32 - (SA) 
ANC can learn a lesson from Moshoeshoe
ON 2004, the University of the Free State turned 100 years old. As part of its centenary celebrations, the idea of the Moshoeshoe Memorial Lecture was mooted as part of another idea: to promote the study of the meaning of Moshoeshoe.

This lecture comes at a critical point in South Africa's still-new democracy. There are indications that the value of public engagement that Moshoeshoe prized highly through his lipitso [community gatherings], and now also a prized feature in our democracy, may be under serious threat. It is for this reason that I would like to dedicate this lecture to all those in our country and elsewhere who daily or weekly, or however frequently, have had the courage to express their considered opinions on pressing matters facing our society. They may be columnists, editors, commentators, artists of all kinds, academics and writers of letters to the editor, non-violent protesters with their placards and cartoonists who put a mirror in front of our eyes.

There is a remarkable story of how Moshoeshoe dealt with Mzilikazi, the aggressor who attacked Thaba Bosiu and failed. So when Mzilikazi retreated from Thaba Bosiu with a bruised ego after failing to take over the mountain, Moshoeshoe, in an unexpected turn of events, sent him cattle to return home bruised but grateful for the generosity of a victorious target of his aggression. At least he would not starve along the way. It was a devastating act of magnanimity which signalled a phenomenal role change.

"If only you had asked," Moshoeshoe seemed to be saying, "I could have given you some cattle. Have them anyway."

It was impossible for Mzilikazi not to have felt ashamed. At the same time, he could still present himself to his people as one who was so feared that even in defeat he was given cattle. At any rate, he never returned.

I look at our situation in South Africa and find that the wisdom of Moshoeshoe's method produced one of the defining moments that led to South Africa's momentous transition to democracy. Part of Nelson Mandela's legacy is precisely this: what I have called counter-intuitive leadership and the immense possibilities it offers for re-imagining whole societies.

A number of events in the past 12 months have made me wonder whether we are faced with a new situation that may have arisen. An increasing number of highly intelligent, sensitive and highly committed South Africans across the class, racial and cultural spectrum confess to feeling uncertain and vulnerable as never before since 1994. When indomitable optimists confess to having a sense of things unhinging, the misery of anxiety spreads. It must have something to do with an accumulation of events that convey the sense of impending implosion. It is the sense that events are spiralling out of control and no one among the leadership of the country seems to have a handle on things.

I should mention the one event that has dominated the national scene continuously for many months now. It is, of course, the trying events around the recent trial and acquittal of Jacob Zuma. The aftermath continues to dominate the news and public discourse. What, really, have we learnt or are learning from it all? It is probably too early to tell. Yet the drama seems far from over, promising to keep us all without relief, and in a state of anguish. It seems poised to reveal more faultlines in our national life than answers and solutions.

We need a mechanism that will affirm the different positions of the contestants validating their honesty in a way that will give the public confidence that real solutions are possible. It is this kind of openness, which never comes easily, that leads to breakthrough solutions, of the kind Moshoeshoe's wisdom symbolises.

Who will take this courageous step? What is clear is that a complex democracy like South Africa's cannot survive a single authority. Only multiple authorities within a constitutional framework have a real chance. I want to press this matter further.

Could it be that part of the problem is that we are unable to deal with the notion of "opposition". We are horrified that any of us could become "the opposition". In reality, it is time we began to anticipate the arrival of a moment when there was no longer a single [overwhelmingly] dominant political force as is currently the case. Such is the course of change. The measure of the maturity of the current political environment will be in how it can create conditions that anticipate that moment rather than ones that seek to prevent it. This is the formidable challenge of a popular post-apartheid political movement.

Can it conceptually anticipate a future when it is no longer overwhelmingly in control, in the form in which it currently is and resist, counter-intuitively, the temptation to prevent such an eventuality? Successfully resisting such an option would enable its current vision and its ultimate legacy to our country to manifest itself in different articulations of itself, which then contend for social influence.

In this way, the vision never really dies, it simply evolves into higher, more complex forms of itself. If the resulting versions are what is called "the opposition" that should not be such a bad thing - unless we want to invent another name for it. The image of flying ants going off to start other similar settlements is not so inappropriate.

I do not wish to suggest that the nuptial flights of the alliance partners are about to occur: only that it is a mark of leadership foresight to anticipate them conceptually. Any political movement that has visions of itself as a perpetual entity should look at the compelling evidence of history. Few have survived those defining moments when they should have been more elastic, and that because they were not, did not live to see the next day.

I believe we may have reached a moment not fundamentally different from the sobering, yet uplifting and vision-making, nation-building realities that led to Kempton Park in the early 1990s. The difference between then and now is that the black majority is not facing white compatriots across the negotiating table. Rather, it is facing itself: perhaps really for the first time since 1994. It is not a time for repeating old platitudes. Could we apply to ourselves the same degree of inventiveness and rigorous negotiation we displayed up to the adoption or our Constitution?

Morena Moshoeshoe faced similarly formative challenges. He seems to have been a great listener. No problem was too insignificant that it could not be addressed. He seems to have networked actively across the spectrum of society. He seems to have kept a close eye on the world beyond Lesotho, forming strong friendships and alliances, weighing his options constantly. He seems to have had patience and forbearance. He had tons of data before him before he could propose the unexpected. He tells us across the years that moments of renewal demand no less.

  • This is an editied version of the inaugural Moshoeshoe Memorial Lecture presented by Univeristy of Cape Town vice-chancellor Professor Ndebele at the University of the Free State on Thursday. Perspectives on Leadership Challenges In South Africa

 

We use cookies to make interactions with our websites and services easy and meaningful. To better understand how they are used, read more about the UFS cookie policy. By continuing to use this site you are giving us your consent to do this.

Accept