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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

Gender bias still rife in African Universities
2007-08-03

 

 At the lecture were, from the left: Prof. Magda Fourie (Vice-Rector: Academic Planning), Prof. Amina Mama (Chair: Gender Studies, University of Cape Town), Prof. Engela Pretorius (Vice-Dean: Humanties) and Prof. Letticia Moja (Dean: Faculty of Health Sciences).
Photo: Stephen Collett

Gender bias still rife in African Universities

Women constitute about 30% of student enrolment in African universities, and only about 6% of African professors are women. This is according to the chairperson of Gender Studies at the University of Cape Town, Prof Amina Mama.

Prof Mama was delivering a lecture on the topic “Rethinking African Universities” as part of Women’s Day celebrations at the University of the Free State (UFS) today.

She says the gender profile suggests that the majority of the women who work in African universities are not academics and researchers, but rather the providers of secretarial, cleaning, catering, student welfare and other administrative and support services.

She said that African universities continue to display profound gender bias in their students and staffing profiles and, more significantly, are deeply inequitable in their institutional and intellectual cultures. She said women find it difficult to succeed at universities as they are imbued with patriarchal values and assumptions that affect all aspects of life and learning.

She said that even though African universities have never excluded women, enrolling them presents only the first hurdle in a much longer process.

“The research evidence suggests that once women have found their way into the universities, then gender differentiations continue to arise and to affect the experience and performance of women students in numerous ways. Even within single institutions disparities manifest across the levels of the hierarchy, within and across faculties and disciplines, within and between academic and administrative roles, across generations, and vary with class and social background, marital status, parental status, and probably many more factors besides these”, she said.

She lamented the fact that there is no field of study free of gender inequalities, particularly at postgraduate levels and in the higher ranks of academics. “Although more women study the arts, social sciences and humanities, few make it to professor and their research and creative output remains less”, she said.

Prof Mama said gender gaps as far as employment of women within African universities is concerned are generally wider than in student enrolment. She said although many women are employed in junior administrative and support capacities, there continues to be gross under-representation of women among senior administrative and academic staff. She said this disparity becomes more pronounced as one moves up the ranks.

“South African universities are ahead, but they are not as radically different as their policy rhetoric might suggest. A decade and a half after the end of apartheid only three of the 23 vice-chancellors in the country are women, and women fill fewer than 30% of the senior positions (Deans, Executive Directors and Deputy Vice-Chancellors)”, she said.

She made an observation that highly qualified women accept administrative positions as opposed to academic work, thus ensuring that men continue to dominate the ranks of those defined as ‘great thinkers’ or ‘accomplished researchers’.

“Perhaps women simply make realistic career choices, opting out of academic competition with male colleagues who they can easily perceive to be systematically advantaged, not only within the institution, but also on the personal and domestic fronts, which still see most African women holding the baby, literally and figuratively”, she said

She also touched on sexual harassment and abuse which she said appears to be a commonplace on African campuses. “In contexts where sexual transactions are a pervasive feature of academic life, women who do succeed are unlikely to be perceived as having done so on the basis of merit or hard work, and may be treated with derision and disbelief”, she said.

She, however, said in spite of broader patterns of gender and class inequality in universities, public higher education remains a main route to career advancement and mobility for women in Africa.

“Women’s constrained access has therefore posed a constraint to their pursuit of more equitable and just modes of political, economic and social development, not to mention freedom from direct oppression”, she said.

Prof Mama concluded by saying, “There is a widely held agreement that there is a need to rethink our universities and to ensure that they are transformed into institutions more compatible with the democratic and social justice agendas that are now leading Africa beyond the legacies of dictatorship, conflict and economic crisis, beyond the deep social divisions and inequalities that have characterised our history”.

She said rethinking universities means asking deeper questions about gender relations within them, and taking concerted and effective action to transform these privileged bastions of higher learning so that they can fulfil their pubic mandate and promise instead of lagging behind our steadily improving laws and policies.

Media Release
Issued by: Mangaliso Radebe
Assistant Director: Media Liaison
Tel: 051 401 2828
Cell: 078 460 3320
E-mail: radebemt.stg@ufs.ac.za  
02 August 2007
 

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