23 June 2021 | Story Leonie Bolleurs | Photo Supplied
The Department of Engineering Sciences (EnSci) – under the leadership of Dr Abdolhossein Naghizadeh – is heading a collaboration of scientists to create a green concrete that will reduce the impact of cement on the environment.

Conventional cement production is responsible for more than 6% of the overall carbon emissions in the world, which ultimately affects global warming.

The Department of Engineering Sciences (EnSci) at the University of the Free State (UFS) – under the leadership of Dr Abdolhossein Naghizadeh – is heading a collaboration of scientists from universities in South Africa and abroad to create a green concrete that will reduce the impact of cement on the environment.

This product has the potential to be used as an alternative to conventional concrete in large-scale constructions such as residential buildings and infrastructure, as well as small-scale constructions such a pavements and brickworks. 

Dr Nagizadeh, whose passion is cement and green concrete, says the idea of eco-friendly concrete was considered by European researchers a few years ago; however, this technology is still in its initial stages and has not been researched and employed at industrial scale yet. He believes that it is due to the complexity of the preparation process, and the relatively aggressive chemicals used in green concrete mixtures.

Expertise and equipment 

With his knowledge and experience of the product, Dr Naghizadeh – who joined EnSci in 2020 – has been appointed project leader of a collaborative group of scientists from the Universities of Johannesburg, KwaZulu-Natal, Yaoundé in Cameroon, and the Erzurum Technical University in Turkey.  

“Since there are only a limited number of researchers in this field, EnSci is benefiting from the expertise of this international collaboration. The proficiency of this group of scientists are keeping the project current, based on the latest findings in the research area,” says Louis Lagrange, Head of the Department of Engineering Sciences. 

Based on this new capacity, the department decided to establish and equip a new laboratory facility dedicated to cement and concrete research, with a specific current focus on green concrete. 

In this laboratory, they want to create formulations of green concrete, based on user-friendly materials. Furthermore, they aim to simplify the preparation and mixing process. “This can introduce a more eco-friendly, desirable product that can easily be employed extensively in the construction industry,” says Lagrange.

Benefits and other advantages

Besides its ability to reduce the impact on the environment through reduced carbon emissions, the product is also described to perform at equal or even superior strength and durability compared to conventional concrete, with potentially substantial environmental and economic benefits. 

This product is also primarily made from waste materials or industrial by-products. Dr Naghizadeh explains it as follows: “Normal concrete consists of conventional (Portland) cement, sand, stone and water, while in green concrete the conventional cement part of the concrete mix is replaced by industrial wastes or by-products and alkali solutions. These alternative materials are mostly aluminosilicate materials such as fly ash (residue from coal burning process in power plants) and slag (waste material from iron extraction processes).”

“Using these waste substances as binding material in green concrete can, apart from the environmental benefits, also reduce waste and contribute to the circular economy. Annually, more than 36 million tons of fly ash are produced in South Africa alone, of which more than 90% is deposited at landfill sites. Reuse of these waste materials will moderate the related waste deposition issues, such as air and groundwater pollution.”

Production of green concrete

Currently, green concrete is mostly produced in two parts: a solid raw material and an alkali activation solution. With their project, the research group wants to develop green concrete in a powdered form, to be mixed with water, instead of a chemical. Dr Nagizadeh estimates that the construction industry will be able to benefit from their work in about two years’ time when they will have a user-friendly green concrete product ready. 

Apart from putting an eco-friendlier concrete on the market, this project is also establishing a brand-new research niche in the UFS Department of Engineering Sciences. According to Lagrange, this research has the ability to attract postgraduate students and other researchers. He is also looking forward to the international academic recognition that EnSci will receive through published articles in leading international journals, and the participation of researchers in accredited conferences arising from this project. 

Lagrange is pleased that the project is establishing EnSci as a research player of note in the engineering field, specifically in the green engineering field. 

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