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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

African Student Affairs Conference a huge success
2011-05-24

 
Mr Rudi Buys, UFS Dean of Student Affairs, Mr. Folabi Obembe, Managing Director of Worldview International, Ms Birgit Schreiber, Director of the Centre for Student support services at the University of the Western Cape, Dr. Augustinah Duyilemi, Dean of Student Affairs at the Adekunleh Ajasin University in Nigeria, Dr. Christina Lunceford, assistant Director for the Centre for Research on Educational Access and Leadership at California State University in America, and Prof. Cecil Bodibe, student affairs veteran and consultant.
Photo: Earl Coetzee

The African Student Affairs Conference (ASAC), which took place on our Main Campus last week, was a major success, with two days of lectures and discussions and two pleasant social gatherings, where delegates had the opportunity to get to know each other.

The conference, hosted on African soil for the first time, and co-hosted by the University of the Western Cape (UWC), started on Wednesday 18 May 2011 with an informal welcoming session. Delegates got to meet each other and Mr Rudi Buys, UFS Dean of Student Affairs, explained the meaning of South African words like "kuier" and "lekker'.

The official start of events took place on Thursday 19 May 2011, in the Reitz Hall in our Centenary Complex. The conference was attended by delegates from universities across the continent and aimed to place the focus on issues relating to student affairs in an African context.

Delegates shared and exchanged strategies, ideas and resources, and discussed issues related to the work of student affairs professionals. The conference hoped to promote an exchange of best practice and assist attendees in identifying successful programmes.

Among the topics discussed on the first day, were “Constructing Post-Conflict Democracy on campus: a case study of transformation of student governance and political engagement as post-conflict intervention”, by Mr. Buys, and a discussion on ways in which social and online media can be used to ease the challenges of student interaction, development and support, by Ms Birgit Schreiber, Director of the Centre for Student Support Services at UWC.

A panel discussion, led by Mr Buys and several members of our Interim Student Council (ISC), discussed the specific challenges faced at the UFS.  The importance of buy-in from role-players in decisions taken by University management in order to ensure their success, was discussed, using the UFS and our recent changes as an example.

The successful integration of residences on campus inevitably came under the spotlight and the recently resolved Reitz-saga was named as a catalyst in getting students less apathetic and more involved in attempts at creating racial and social harmony.

Dr Christina Lunceford, Assistant-Director of the Centre for Research on Educational Access and Leadership at California State University, presented a paper entitled A National Approach to Building Capacity in Student Affairs in South African Higher Education.

She commented on the fact that there is little or no philosophical framework or explicit theory that informs practice of student services in South Africa.

According to Dr Lunceford, student development should be a key concern for every department or unit within student services and emphasized the need for a centralized student development unit at each university.
She also touched on the need for institutions to implement support from international student affairs professional associations, professional development for student affairs practitioners, the utilization of technology to support professionals in the field, and working with international partners to explore future opportunities, as ways in which student affairs can be used to drive performance and change at universities.

The conference continued in the Scaena theatre on Friday 20 May 2011, with presentations by Dr Augustinah Duyileme, Dean of Student Affairs at Adekunle Ajasin University in Nigeria, and Prof. Bobby Mandew, Executive Director of Student Affairs at the University of Johannesburg (UJ).

Dr Duyileme presented a paper on the challenges faced by Nigerian universities with regard to student conflict and protests, which often turn violent, and how such violence can be curbed through proper planning and management.

Prof. Mandew presented a very well-received presentation on UJ’s successful off-campus housing initiative, which involves home-owners and business owners in the areas surrounding their campuses.

Their approach demonstrated how proper planning can prevent problems associated with over-population in private homes and conflict with neighbours of the university, usually related to an influx of students into residential neighbourhoods.

This problem is faced by many universities, as more and more students flock to universities on the continent and campus residents cannot accommodate them.

The conference came to a close on Friday, with most delegates agreeing that the exchange of knowledge which took place was extremely valuable.

Ms Deborah Lahlan, of Nigeria, said: “This is an important conference for Africa and it should become a regular event.”
 

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