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Green Engineering: How UFS’s Green concrete can be an alternative to OPC cement

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

Conference: Expanded ARV treatment

2005-03-02

VENUE: University of the Free State, Bloemfontein, South Africa
DATE: 30 March 2005 - 1 April 2005

ARV Programme as on 24Feb Download Word document
Programme Special events Download Word document

Official web site www.fshealth.gov.za/subsites/arvc

Rationale for the Conference
At the time of the planned Conference, much ground would have been covered, both in the Free State and in South Africa, in respect of the expanded public sector ARV treatment programme in respect of research, experiences in practice, training of staff, treatment of patients, lessons learned, successes and failures, etc. The time would then be quite opportune to share these in a systematic manner with other provinces and countries, as well as with the large variety of stakeholders and role players in the ARV and related domains, be they academics and researchers, policy makers and service/facility managers, the variety of caregivers, and the community organisations and affected patients.

The Conference and current research
The proposed Conference is, firstly, directly linked to the current research on the public sector roll-out of ARV treatment in the Free State conducted by several research institutions (e.g. CIET, CHSR&D, UCT Lung Institute). Secondly, the Conference could and would serve as a forum for other research groups in the country and further a field to report and share knowledge and experiences on ARV treatment and related initiatives. Lastly, the Conference will stage a golden opportunity for researchers and scientists, on the one hand, and policy makers, managers, and caregivers (as knowledge users), on the other hand, to engage in cross-disciplinary discourse on this mutual and topical theme.

Theme of Conference
Expanded ARV treatment in the Free State: sharing experiences

Focus
The focus is primarily on public sector ARV treatment in the Free State, but also initiatives/activities/perspectives of relevance to the Free State elsewhere in the country at large and further a field, as well as relevant ARV initiatives in the public, private, NGO and FBO sectors. Bear in mind, however, that ARV treatment is but part of a much more comprehensive approach to HIV and AIDS. The Conference will, therefore, not narrowly focus on the ARV treatment programme only. The broader context, other relevant dimensions, and a comprehensive approach to the challenges of HIV, AIDS and TB are of equal importance.

The purpose of the Conference
Enhance meaningful exchange, mutual understanding and collaboration among researchers, scientists, policy makers, managers and practitioners in the field of ARV treatment and related fields.

Share experiences in the various spheres of ARV treatment and related spheres (policy, management, practice, research, training, public-private-civil society sectors).

Record, reflect and report on the establishment of the ARV treatment programme in the Free State, and in within the context of the comprehensive HIV/AIDS programme.

Disseminate important research results on ARV treatment and related themes to health policy makers, managers, practitioners, communities and to the research community.

Stimulate discourse among various disciplines and various stakeholders/role players involved in ARV treatment and related programmes.

Sensitise and acquaint researchers to the requirements of policy makers, managers and practitioners in respect of ARV treatment and related fields.

Facilitate the implementation of research results in ARV treatment policy, programmes and practice.

Dissemination of Conference-related information
Information generated during the Conference could feed into policy, management and practice of ARV treatment, the training accompanying such programme, and the existing body of knowledge. After the Conference the information will be disseminated via the Internet and by scientific and popular publications.

Date and duration
Set for 30 & 31 March & 1 April 2005; to commence at 09:00 on the first day (30 March) and to end at 16:30 (1 April) the third day.

Format and scope of Conference
Alternating plenary, parallel sessions and debates focused on topical issues and interest groups. The Conference will strive to be maximally interactive and participative.

Themes and topics to cover:

Policy, management and health services/practice (various levels and contexts – clinical treatment, information, IT systems, pharmacy, laboratories, nutrition)
Research covering all relevant disciplines and diverse dimensions of ARV treatment and related themes
Training and evaluation of training
Patients, communities and civil society organisations
Public, private, NGO, FBO initiatives and partnerships

Emphasis will be on the Free State, however, with of significant involvement from other provinces, SADC countries, and countries further a field. The thrust will be to export lessons and experiences from the Free State, but also to import lessons and experiences from other provinces, countries and sectors.

Presenters
Key presenters from the Free State, other provinces, South Africa, from the private, FBO and NGO sectors, and from several other countries

Delegates
About half of the delegates will be Free State stakeholders and role players (all levels and all contexts). The other half will be role players and stakeholders in the ARV and related fields from other provinces, the national level, and other countries, as well as from the private, public and non-governmental sectors.

Focused workshops
Provision will be made for half-a-day or one-day workshop initiatives on the third day (1 April 2005).

Enquiries
For more information please contact:

Prof Dingie van Rensburg
Centre for Health Systems Research & Development
University of the Free State
PO Box 339
Bloenfontein
SOUTH AFRICA
9300

Contact:
Carin van Vuuren
Conference Organiser
Centre for Health Systems Research & Development
University of the Free State
P.O.Box 339
Bloemfontein
South Africa
9300
Tel +27 (0) 51 401 2181
Fax +27 (0) 51 4480370
Cell 0832932890
e-mail: arvconference.hum@mail.uovs.ac.za

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