Latest News Archive

Please select Category, Year, and then Month to display items
Previous Archive
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

Inaugural lecture: Prof. Annette Wilkinson
2008-04-16

A strong plea for a pursuit of “scholarship” in higher education

Prof. Annette Wilkinson of the Centre for Higher Education Studies and Development in the Faculty of the Humanities at the University of the Free State (UFS) made as strong plea for a pursuit of “scholarship” in higher education.

She said in her inaugural lecture that higher education has to deal with changes and demands that necessitate innovative approaches and creative thinking when it concerns effective teaching and learning in a challenging and demanding higher education environment. She referred to a recent research report prepared for the Council for Higher Education (CHE) which spells out the alarming situation regarding attrition rates and graduation output in South African higher education and emphasises factors leading to the situation. These factors include socio-economic conditions and shortcomings in the school and the subsequent under preparedness of a very large proportion of the current student population. However, what is regarded as one of the key factors within the sector’s control is the implementation of strategies for improving graduate output.

She said: “The CHE report expresses concern about academics’ adherence to traditional teaching practices at institutions, which have not changed significantly to make provision for the dramatic increase in diversity since the 1980s.

“Raising the profile of teaching and learning in terms of accountability, recognition and scholarship is essential for successful capacity-building,” she said. “The notion of scholarship, however, brings to the minds of many academics the burden of ‘publish or perish’. In many instances, the pressures to be research-active are draining the value put on teaching. Institutions demand that staff produce research outputs in order to qualify for any of the so-called three Rs – resources, rewards and recognition.

“These have been abundant for research, but scarce when it comes to teaching – with the status of the latter just not on the same level as that of research. From within their demanding teaching environments many lecturers just feel they do not have the time to spend on research because of heavy workloads, that their efforts are under-valued and that they have to strive on the basis of intrinsic rewards.”

She said: “It is an unfortunate situation that educational expertise, in particular on disciplinary level, is not valued, even though in most courses, as in the Programme in Higher Education Studies at the UFS, all applications, whether in assignments, projects or learning material design, are directly applied to the disciplinary context. We work in a challenging environment where the important task of preparing students for tomorrow requires advanced disciplinary together with pedagogical knowledge.”

Prof. Wilkinson argued that a pursuit of the scholarship of teaching and learning holds the potential of not only improving teaching and learning and consequently success rates of students, but also of raising the status of teaching and recognising the immense inputs of lecturers who excel in a very demanding environment. She emphasised that not all teaching staff will progress to the scholarship level or are interested in such an endeavour. She therefore suggested a model in which performance in the area of teaching and learning can be recognised, rewarded and equally valued on three distinct levels, namely the levels of excellence, expertise and scholarship. An important feature of the model is that staff in managerial, administrative and support posts can also be rewarded for their contributions on the different levels for all teaching related work.

Prof. Wilkinson also emphasised the responsibility or rather, accountability, of institutions as a whole, as well as individual staff members, in providing an environment and infrastructure where students can develop to their full potential. She said that in this environment the development of the proficiency of staff members towards the levels of excellence, expertise and scholarship must be regarded as a priority.

“If we want to improve students’ success rates the institution should not be satisfied with the involvement in professional development opportunities by a small minority, but should set it as a requirement for all teaching staff, in particular on entry into the profession and for promotion purposes. An innovative approach towards a system of continuous professional development, valued and sought after, should be considered and built into the institutional performance management system.”

As an example of what can be achieved, Prof. Wilkinson highlighted the work of one of the most successful student support programmes at the UFS, namely the Career Preparation Programme (CPP), implemented fourteen years ago, bringing opportunities to thousands of students without matric exemption. The programme is characterised by dedicated staff, a challenging resource-based approach and foundational courses addressing various forms of under preparedness. Since 1993 3 422 students gained entry into UFS degree programmes after successfully completing the CPP; since 1996 1 014 of these students obtained their degrees, 95 got their honours degrees, 18 their master’s degrees and six successfully completed their studies as medical doctors.

Prof. Wilkinson said: “I believe we have the structures and the potential to become a leading teaching-learning university and region, where excellence, expertise and scholarship are recognised, honoured and rewarded.”

 

We use cookies to make interactions with our websites and services easy and meaningful. To better understand how they are used, read more about the UFS cookie policy. By continuing to use this site you are giving us your consent to do this.

Accept