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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

Association of Former SRC Presidents – first of its kind
2013-08-19

 

Some of the former SRC presidents who attended the inaugural dinner were, from the left: Roelf Meyer, Bloemfontein Campus 1970; Dr More Chakane, Qwaqwa Campus 1990; vice-chairperson of the AFSP; Dr Anchen Laubscher, first woman president of the Bloemfontein Campus 2003; and Prof Voet du Plessis, Bloemfontein Campus 1967/8.
Photo: Stephen Collett
19 August 2013

The University of the Free State (UFS) made history this weekend with the establishment of its Association of Former SRC Presidents (AFSP) – the first association of its kind after the merging and incorporation of public institutions in 2003–2004.

Twenty-two former SRC presidents attended the inaugural dinner to launch the association on Women's Day, Friday 9 August 2013, and recognised especially the attendance of all four female presidents that previously chaired the SRC. Other guests included former rectors and chairpersons of the UFS Council, as well as chairpersons of the Alumni.

The attending presidents served during the period 1967–2012, either at the former University of the Orange Free State (UOFS), the Qwaqwa Campus of the former University of the North, South Campus of the former Vista University and the University of the Free State.

“Your very personal narratives as former student leaders during the troubled past of our history in South Africa matter most as you design the questions for and purpose of an authentic conversation with student leaders today – this will set your association apart from others," said Rudi Buys, Dean of Student Affairs.

Former SRC president of 1975/6 and now founding member and chairperson of the association, Dr Michiel Strauss, said that this is the opportunity for former student leaders to give back to the younger generation.

“It is true that many middle-aged white South Africans have a deep sense of debt and obligation towards the youth of our country. We owe them an apology for the discrepancies of the past. This apology should be more than just words. Deeds of reconciliation and restitution must be seen.

“As for myself; I was president of the SRC of the then UOFS in the same period in which the biggest part of the youth of South Africa suffered so much in their struggle for freedom in our country.

“In my personal capacity, as well as in my official capacity as SRC president, I did nothing to try and understand and/or co-operate in the struggle of my peers. This fact haunts me until this day.

“The question then for people like me and so many others, is: Where do I invest my time and energy and passion for this country? Where will my contribution make a real difference? There is no better answer to this burning question than to invest in the human resources in our beloved South Africa, and more focused – to invest in the young people.

“There is something meaningful and beautiful happening at the UFS and it is now a leader in academic standards, reconciliation, leadership formation and nation building. I can think of no better place to make my small contribution,” Dr Strauss said.

“As former student leaders, we have a sense of purpose to contribute to the university and there is no better time to start than now. It is my privilege to be part of this great initiative and I look forward to what will be achieved,” said Dr More Chakane, deputy chairperson of AFSP and former SRC president of the Uniqwa Campus of the University of the North in 1990 (now the Qwaqwa Campus of the UFS).

Roelf Meyer, known for the prominent role he played in the negotiations to end apartheid in South Africa and chairperson of the Civil Society Initiative (CSI) of South Africa, said his time as a leader at the university has given him the opportunity to apply and use his skills and experience and share it with the new leaders of the institution. "The UFS is highly regarded because of the exceptional standards and excellence portrayed by its senior leadership. Where I can make a difference, I'll do it with pleasure and pride," he said. Meyer served as SRC president in 1970.

The association met on Saturday 10 August 2013 to adopt its interim constitution and consider operational matters, while also reaching agreement on its core functions in support of its purpose to transfer change leadership skills to incumbent student leaders and mediate meaningful contributions of Alumni to the growth of the university.

“We greatly value the declared intention of AFSP to work with the university to design meaningful and sustainable mentorship programmes to support and guide student leaders on campus, and have pledged our support in this regard,” said Buys.

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