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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

Future Leader’s Award 2017 goes to UFS Quantity Surveying student
2017-08-11

Description: Future Leader’s Award 2017 goes to UFS Quantity Surveying student Tags: Future Leader’s Award 2017 goes to UFS Quantity Surveying student 

Celebrating big achievements in the construction
sector at the recent Association of South African
Quantity Surveyors (ASAQS) conference are, from
the left: Cameron Ferreira, junior lecturer in the
UFS Department of Quantity Surveying,
Jhon Thatcher, former UFS student in the same
department who was the second runner-up for the
Gold Medal Award, Dr Stephan Ramabodu, President
of ASAQS, Gerné Bothma, former student in the
department and winner of the Future Leaders’
Award 2017, and Pierre Oosthuizen, UFS lecturer in
the same department.
Photos: Supplied


The Department of Quantity Surveying and Construction Management at the University of the Free State (UFS) made good on its promise to develop independent and critical-thinking graduates who will become leaders in their field. At the recent Association of South African Quantity Surveyors (ASAQS) conference and gala dinner, two students from the department, Gerné Botma and Jhon Thatcher, received awards for their outstanding performance.

Best of the best
Botma received the ASAQS Future Leaders’ Award (2017), an award based on academic achievement in the first three years of study. He competed with nominees from universities across South Africa offering Quantity Surveying programmes, and was the winner in this category.

Thatcher was a second runner-up for the ASAQS Gold Medal Award (being in the top three Quantity Surveying students in South Africa). This is awarded on a number of criteria, including academic achievement. Fourth-year students from all the universities in South Africa offering Quantity Surveying programmes compete for this award, and must display achievement in categories such as academia, leadership, community engagement, and general interests.  In 2016, the Gold Medal Award was won by the UFS student, Kamogelo Leeuw.

Keeping abreast of developments
Today, organisations are relying on its members to stay ahead of issues, technologies, innovations and trends. In Quantity Surveying, to keep abreast of developments in the built environment, ASAQS was established as a voluntary association, with one of its goals being advancing and promoting the science and practice of Quantity Surveying.  ASAQS works in close collaboration with its member firms, tertiary institutions, and the South African Council for Quantity Surveying Professions (SACQSP), a statutory body that oversees and regulates the profession, and accredit Quantity Surveying programmes in South Africa.

Two staff members from the UFS Department of Quantity Surveying and Construction Management, Cameron Ferreira and Pierre Oosthuizen, attended the recent ASAQS annual conference. Ferreira, a junior lecturer in the department, is the current Chapter Chairperson of the Free State for ASAQS and Oosthuizen, a lecturer in the department, is the former Chapter Chairperson.

According to Ferreira, they attended the conference to keep abreast of the latest development within the industry. “The event also served as a great networking opportunity for the UFS to build partnerships with other industry pioneers,” she said. Making use of opportunities such as these is in line with the UFS’s pursuit of lifelong learning.

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