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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

Launch of the Africa office of the IIDE
2006-05-25

Attending the launch of the Africa office of the IIDE were from the left Prof Sytse Strijbos (Chairperson of IIDE Europe), Rev Kiepie Jaftha (Chairperson of the IIDE in Africa’s Board of Directors and Chief Director: Community Service at the UFS) and Prof Frederick Fourie (Rector and Vice-Chancellor of the UFS).

 

Attending the launch were from the left Prof Lucius Botes (Director: Centre of Development Support at the UFS), Dr Samuel Kareithi (Head: Community Development at the Cornerstone Christian College, Cape Town), Rev Kiepie Jaftha (Chairperson of the IIDE in Africa’s Board of Directors and Chief Director: Community Service at the UFS), Prof Sytse Strijbos (Chairperson of IIDE Europe) and Dr Ezekiel Moraka (Vice-Rector:  Student Affairs at the UFS).

Africa office of IIDE launched on UFS main campus 

The Africa office of the International Institute for Development and Ethics (IIDE) was today (26 May 2006) launched on the Main Campus of the University of the Free State (UFS) in Bloemfontein.

“The IIDE specialises in the studying and research of general questions of developmental theory and practices and provides services and support in education, strategic planning, policy formulation, advocacy and capacity building of development agencies,” said Rev Kiepie Jaftha, Chairperson of the IIDE in Africa’s Board of Directors and Chief Director: Community Service at the UFS.

According to Rev Jaftha the IIDE in Africa will focus on the conceptual and normative aspects of developmental processes in Sub-Saharan Africa.  “We want to foster local and international partnerships with various relevant role-players in civil society, the private sector and public sector in the SACD region and later expand our operations to the rest of Africa,” said Rev Jaftha.

The IIDE in Africa cooperates with a similar foundation in Europe, functioning as the IIDE Europe.  This institute was founded in 2003 and its head office is situated in the Netherlands.  The UFS is a funder of the IIDE in Africa together with the Paul Foundation and private sponsors from the Netherlands.

“We have already started with various projects which are in various stages of implementation,” said Rev Jaftha.  Some of these projects include, among others, the broadening of the master’s degree in Christian Studies of Science and Society (MACSSS) which is currently housed at the Vrije Universiteit in Amsterdam to tertiary institutions in South Africa such as the UFS, the University of Stellenbosch and the Potchefstroom Campus of the Northwest University.

“Another project is an investigation into the possibility of initiating a broad development initiative in the poverty stricken Qwaqwa area.  This initiative will attempt to concentrate on issues like the training and empowerment of prospective entrepreneurs in the region, the identification of prospective entrepreneurs for the rendering of development support and the monitoring of the impact of information and communication technology on local communities during the implementation of sustainable development initiatives,” said Rev Jaftha.

“The establishment of the Africa office of the IIDE on the UFS Main Campus is an indication of one of the aims of the UFS to play a role in South Africa and Africa.  It also signifies our aim to contribute meaningfully to research and development and to establish links between the academe and practice,” said Rev Jaftha. 

 

Media release
Issued by: Lacea Loader
Media Representative
Tel:   (051) 401-2584
Cell:  083 645 2454
E-mail:  loaderl.stg@mail.uovs.ac.za
26 May 2006

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