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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

Moshoeshoe film screened at UFS as part of transformation programme
2004-10-14

A ground-breaking documentary film on the life and legacy of King Moshoeshoe I, the founder of the Basotho nation, will be screened at the University of the Free State (UFS) tonight (Wednesday 13 October 2004) at 19:00.

Rector and Vice-Chancellor of the UFS, prof. Frederick Fourie, said the UFS commissioned the documentary as a practical demonstration of the university’s commitment to the continued transformation of the campus and the creation of a new inclusive institutional culture for all staff and students.

It is part of a larger UFS project to honour the Moshoeshoe legacy of nation-building and reconciliation and to explore his role as a model of African leadership.

The documentary tells the life story of the legendary king, with emphasis on his remarkable leadership skills, his extraordinary talent for diplomacy and conflict resolution and his visionary commitment to creating a new nation from a fragmented society.

Almost all the filming was done on or around Moshoeshoe’s mountain stronghold, Thaba Bosiu.

The last part of the documentary explores the lessons for African leadership to be learnt from Moshoeshoe. The hour-long documentary film was produced by the well-known journalist Mr Max du Preez and was commissioned by the UFS as part of its centenary celebrations.

“Through this documentary film about King Moshoeshoe, the UFS commits itself to developing a shared appreciation of the history of this country,” said prof. Fourie.

“King Moshoeshoe was a great African statesman and leader. He was born in this region of the country, but his influence and legacy extends way beyond the borders of the Free State, Lesotho and even way beyond the borders of South Africa,” said prof. Fourie.

As part of the larger project, the UFS is investigating a possible annual Moshoeshoe memorial lecture that will focus on African leadership, nation-building and reconciliation, possible PhD-level research into the life and legacy of King Moshoeshoe and a literary anthology including prose and poetry.

“We must gain a deeper understanding of what really happened during his reign as king. Therefore the University of the Free State will encourage and support further research into the history, politics and sociology of the Moshoeshoe period, including his leadership style,” said prof. Fourie.

According to prof. Fourie the Moshoeshoe project will enable the UFS to give real meaning to respect for the diversity of our languages and cultures, and the unity South Africans seek to build as a democratic nation through such diversity.

According to the producer of the documentary, journalist Mr Max du Preez, the UFS deserves credit for recognising this extraordinary man and for financing this important documentary.

Du Preez said: “It was about time that South Africa rediscovered Moshoeshoe. Colonialist and Afrikaner Nationalist historians have painted him as a sly, untrustworthy and weak leader. Most historians have preferred to glorify leaders in South Africa’s past who were aggressors and conquerors. In the process most present-day South Africans came to regard Moshoeshoe as a minor tribal figure.”

“Yet this was the man who broke the cycle of violence, famine and suffering during the traumatic time in central South Africa in the early 1800s. During the entire 19th century, Moshoeshoe was virtually the only leader in South Africa who did not answer violence with violence, who did not set forth to conquer other groups and expand his land,” said Mr du Preez.

“I have no doubt that the stability that the Free State region has enjoyed over more than a century was largely due to Moshoeshoe’s leadership and vision. He can quite rightly be called “The Nelson Mandela of the 19th Century,” Mr du Preez added.

Explaining the title of the documentary film, Mr du Preez said: “We decided to call the documentary “The Reniassance King” because whichever way one looks at it, Moshoeshoe symbolised everything behind the concept of an African Renaissance.”

“He was progressive, just and fair; he deeply respected human life and dignity (we would nowadays call it human rights); he embraced modernity and technology without ever undermining his own people’s culture or natural wisdom; he never allowed European or Western influence to overwhelm him, make him insecure or take away his pride as an African,” said Mr du Preez.

“Moshoeshoe was the best of Africa. If only contemporary African leaders would follow his example of what African leadership should be,” Mr du Preez said.

Among the interviewees in the film were Lesotho’s most prominent historian, Dr LBBJ Machobane, the head of the UFS’s Department of History, prof. Leo Barnard, Moshoeshoe expert and Gauteng educationist Dr Peter Seboni, Lesotho author and historian Martin Lelimo and Chief Seeiso Bereng Seeiso, Principal Chief of Matsieng and direct descendant of the first King of the Basotho.

The documentary film on King Moshoeshoe will be screened on SABC 2 on Thursday 4 November 2004.
 

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