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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

The failure of the law
2004-06-04

 

Written by Lacea Loader

- Call for the protection of consumers’ and tax payers rights against corporate companies

An expert in commercial law has called for reforms to the Companies Act to protect the rights of consumers and investors.

“Consumers and tax payers are lulled into thinking the law protects them when it definitely does not,” said Prof Dines Gihwala this week during his inaugural lecture at the University of the Free State’s (UFS).

Prof Gihwala, vice-chairperson of the UFS Council, was inaugurated as extraordinary professor in commercial law at the UFS’s Faculty of Law.

He said that consumers, tax payers and shareholders think they can look to the law for an effective curb on the enormous power for ill that big business wields.

“Once the public is involved, the activities of big business must be controlled and regulated. It is the responsibility of the law to oversee and supervise such control and regulation,” said Prof Gihwala.

He said that, when undesirable consequences occur despite laws enacted specifically to prevent such results, it must be fair to suggest that the law has failed.

“The actual perpetrators of the undesirable behaviour seldom pay for it in any sense, not even when criminal conduct is involved. If directors of companies are criminally charged and convicted, the penalty is invariably a fine imposed on the company. So, ironically, it is the money of tax payers that is spent on investigating criminal conduct, formulating charges and ultimately prosecuting the culprits involved in corporate malpractice,” said Prof Gihwala.

According to Prof Gihwala the law continuously fails to hold companies meaningfully accountable to good and honest business values.

“Insider trading is a crime and, although legislation was introduced in 1998 to curb it, not a single successful criminal prosecution has taken place. While the law appears to be offering the public protection against unacceptable business behaviour, it does no such thing – the law cannot act as a deterrent if it is inadequate or not being enforced,” he said.

The government believed it was important to facilitate access to the country’s economic resources by those who had been denied it in the past. The Broad Based Economic Empowerment Act of 2003 (BBEE), is legislation to do just that. “We should be asking ourselves whether it is really possible for an individual, handicapped by the inequities of the past, to compete in the real business world even though the BBEE Act is now part of the law?,” said Prof Gihwala.

Prof Gihwala said that judges prefer to follow precedent instead of taking bold initiative. “Following precedent is safe at a personal level. To do so will elicit no outcry of disapproval and one’s professional reputation is protected. The law needs to evolve and it is the responsibility of the judiciary to see that it happens in an orderly fashion. Courts often take the easy way out, and when the opportunity to be bold and creative presents itself, it is ignored,” he said.

“Perhaps we are expecting too much from the courts. If changes are to be made to the level of protection to the investing public by the law, Parliament must play its proper role. It is desirable for Parliament to be proactive. Those tasked with the responsibility of rewriting our Companies Act should be bold and imaginative. They should remove once and for all those parts of our common law which frustrate the ideals of our Constitution, and in particular those which conflict with the principles of the BBEE Act,” said Prof Gihwala.

According to Prof Gihwala, the following reforms are necessary:

• establishing a unit that is part of the office of the Registrar of Companies to bolster a whole inspectorate in regard to companies’ affairs;
• companies who are liable to pay a fine or fines, should have the right to take action to recover that fine from those responsible for the conduct;
• and serious transgression of the law should allow for imprisonment only – there should be no room for the payment of fines.
 

Prof Gihwala ended the lecture by saying: “If the opportunity to re-work the Companies Act is not grabbed with both hands, we will witness yet another failure in the law. Even more people will come to believe that the law is stupid and that it has made fools of them. And that would be the worst possible news in our developing democracy, where we are struggling to ensure that the Rule of Law prevails and that every one of us has respect for the law”.

 

 

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