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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

Faculty of Law establishes unique panel of advisors
2005-11-11

Photo: Stephen Collett

Some of the panel members who attended the Collegium Iurisprudentium of the Faculty of Law at the UFS were from the left His Honorable Judge of Appeal Lex Mpati (Vice-President of the Supreme Court of Appeal), His Honorable Judge of Appeal Joos Hefer (former Chief Justice of South Africa), His Honorable Judge of Appeal Frits Brand (Supreme Court of Appeal) and Mrs Alet Ellis (lecturer at the UFS Faculty of Law).

At the back from left were Prof Johan Henning (Dean: Faculty of Law at the UFS), His Honorable Judge Faan Hancke (High Court of the Free State and chairperson of the UFS Council) and Adv Jannie Lubbe Sc.

The Faculty of Law at the University of the Free State (UFS) has established a panel of advisors comprising of all the honorary and extraordinary professors of the faculty.

“The faculty has been known for its excellent practice-orientated training as well as the involvement of law practitioners in the training of LL B-students,” said Prof Johan Henning, Dean of the Faculty of Law at the UFS.

“The faculty was greatly dependent on the services of advocate lecturers, full-time members of the Bar and Side Bar who lectured on a part-time basis at the faculty.  For this reason lecturing in the faculty was mainly done after-hours to part-time students,” said Prof Henning. 

With the shift in emphasis to full-time lecturing and the appointment of full-time lecturers, especially because of the increasing student numbers, the full-time LL B-programme and the increasing pressure on students for quality research inputs, a greater need for meaningful contributions of judges and senior law practitioners to the faculty was experienced.

“To comply with this urgent need, three honorary professors and nine extraordinary professors were appointed.  This group of experts deliver an indispensable contribution to the practice orientation of the faculty by means of formal lectures, public inaugural lectures and guest lectures, direct lectures to graduate and post-graduate students, participation in research projects and the  constant evaluation of lecturers, modules and the content of modules and learning material. The international exposure of students and lecturers is also promoted by their contribution,” said Prof Henning.
“A need to have the involvement of this special class of professors structured in a more organised way was identified and a decision was made to establish an advisory panel called Collegium Iurisprudentium.  It is a privilege to us that all the honorary and extraordinary professors accepted the invitation,” said Prof  Henning. 

The panel will provide the faculty with continuous, distinguished, practice- orientated capability and capacity as well as international expertise, not only for direct inputs to students but also to advise lecturers about the curriculum, the compilation of the content of the LL B and M module, learning material and others, as well as to strengthen the research capacity of the faculty.

“The panel will also deliver a decisive contribution to the faculty’s preparation for the constitutional audit of the Higher Education Quality Committee (HEQC) of the Council for Higher Education (CHE) that will take place in October 2006,” said Prof Henning. 

The Collegium Iurisprudentium, which has been formally constituted, comprises of:

Appeal Court Judge J J F Hefer,
Appeal Court Judge L Mpati
Appeal Court Judge F D J Brand
Appeal Court Judge I G Farlam
Prof B A K Rider
Judge S P B Hancke
Judge A Kruger
Judge D H van Zyl
Adv S J Naudé
Adv J Lubbe Sc
Prof M M Katz
Prof R J Cook
Mr S van de Merwe
Mr W van der Westhuizen
Mr D C M Gihwala

Media release
Issued by:Lacea Loader
Media Representative
Tel:  (051) 401-2584
Cell:  083 645 2454
E-mail:  loaderl.stg@mail.uovs.ac.za
11 November 2005

 

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