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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

In January 1, 2003, the Qwa-Qwa campus of the University of the North (Unin) was incorporated into the University of the Free State (UFS).
2003-02-07


FREDERICK FOURIE

IN January 1, 2003, the Qwa-Qwa campus of the University of the North (Unin) was incorporated into the University of the Free State (UFS).

While this is merely the beginning of a long and complex process, it does represent a major milestone in overcoming the apartheid legacy in education, realising the anti-apartheid goal of a single non-racial university serving the Free State.

The incorporation is also part of the minister's broader restructuring of the higher education landscape in South Africa - a process which aims to reshape the ideologically driven legacy of the past.

In contrast to the past educational and social engineering that took place, the current process of incorporating the Qwa-Qwa campus of Unin into the UFS is informed by three fundamentally progressive policy objectives, clearly outlined in the education white paper 3: (A framework for the transformation of higher education):

To meet the demands of social justice to address the social and structural inequalities that characterise higher education.

To address the challenges of globalisation, in particular the role of knowledge and information processing in driving social and economic development.

To ensure that limited resources are effectively and efficiently utilised, given the competing and equally pressing priorities in other social sectors.

Besides informing the way the UFS is managing the current incorporation, these policy objectives have also informed the transformation of the UFS as an institution over the past five years.

In 2001, former president Nelson Mandela lauded the success of the UFS in managing this transformation, by describing the campus as a model of multiculturalism and multilingualism. This was at his acceptance of an honorary doctorate from the UFS.

Indeed our vision for the Qwa-Qwa campus as a branch of the UFS is exactly the same as it is for the main UFS campus - a model of transformation, academic excellence, community engagement and financial sustainability, building on the histories and strengths of both the Qwa-Qwa campus and the UFS (Bloemfontein campus).

Realising this vision will be a giant leap forward in establishing a unified higher education landscape in the Free State.

In more concrete terms, the UFS is working towards this vision by focusing on the following areas of intervention: access and equity; academic renewal; investment in facilities; and sound financial management.

These interventions are being made not to preserve any vestiges of privilege or superiority, but precisely to increase access for students from poor backgrounds and to promote equity and representivity among all staff.

The current growth phase of the UFS has seen student enrolment almost double over the past five years, in particular black students, who now constitute approximately 55 percent of the student population of nearly 18 000 (including off-campus and online students).

But it has not just been a numbers game. Our approach has been to ensure access with success.

Our admissions policy, coupled with the academic support and "career preparation" programmes we offer, have resulted in significant successes for students who otherwise would not have been allowed to study at a university.

This will be continued at Qwa-Qwa as well.

Our academic offerings too have undergone dramatic change. We have become the first university in the country to offer a degree programme based on the recognition of prior learning (RPL).

This is not just a matter of academic renewal but of access as well, especially for working adults in our country who were previously denied a university education.

As for the sound financial management of the UFS (including the Qwa-Qwa campus), this is being done not for the sake of saving a few rands and cents, but for the greater value to our society that comes from having sustainable institutions.

It is sustainable universities that can make long-term investments to fund employment equity, provide information technology for students, upgrade laboratories, construct new buildings, develop research capacity, and provide a safe environment for students and staff, as is happening now at the UFS.

As a result of such management, a practical benefit for prospective students at the Qwa-Qwa campus of the UFS will be lower academic fees in some cases compared with the Unin fees.

As is the case with all these processes, there are concerns from staff and students at Qwa-Qwa and the broader community of the region that the Qwa-Qwa campus serves.

To get the campus viable and to ensure its continuation in the short term, tough choices had to be made by the minister of education regarding which programmes to offer and fund.

But we have been encouraged by the community's understanding that these concerns can be addresed over time as the campus becomes financially viable.

Meetings between the top mangement of the UFS and community representatives, staff and students at Qwa-Qwa have laid the basis for building a climate of trust in such a complex process.

We should not be captives of the past divisions but build this new unified higher education landscape that can meet our country's developmental needs.

It should be a higher education landscape that is based on broadening access, promoting equity and social justice, developing academic excellence, and the effective and efficient management of scarce resources. This should be our common common objective.

Professor Frederick Fourie the rector and vice-chancellor of the University of the Free State (UFS)

 

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