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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

State of our campuses: UFS closes campuses until Friday 28 October 2016 to readjust academic programme

2016-10-15

UFS announces strategy for completion of the 2016 academic year

Agreement between UFS management and student leadership in relation to residences

After almost four weeks of student protests about fees at the University of the Free State (UFS) and the subsequent suspension of the academic programme and closing of campuses, the senior leadership announced on 14 October 2016 a strategy to ensure that students will be able to complete the 2016 academic year.

The university on 13 October 2016 announced that it will shut down its Bloemfontein and South Campuses until 28 October 2016 for crucial and complex arrangements to be put in place to readjust the academic calendar and ensure that all students can complete their studies. The senior leadership did, however, make it clear that the university will not be shutting down for the remainder of 2016.

No teaching and learning activities at undergraduate and honours level will be offered between 17 October and 28 October 2016. The university will re-start teaching and learning at undergraduate and honours level in the first week of November 2016.

However, teaching and learning will not take place in the classrooms during November 2016, but through a different mode of delivery that consists of a combination of printed and recorded lectures, study materials and learning aids that will be provided by the university and delivered through Blackboard. In this manner no attempts at disrupting the rest of the academic year will affect our students’ academic programme. Students, however, will sit for the exam on campus.

Students in residence accommodation can return to campus as from 29 October 2016 and it is recommended that students who do not have off-campus internet access return to campus in order to access study material to complete the academic year.A new timetable for exams is still being developed and will be communicated as soon as the arrangements have been finalised.

Faculties have been differently affected by the loss of teaching time. Some faculties like the Faculty of Law have completed their curriculum, while other faculties like the Faculty of Natural and Agricultural Sciences require more teaching time. Some faculties, like the Faculty of Health Sciences, cannot do teaching through alternative modes of delivery.

The needs of the different faculties have been taken into account for developing a rescue plan to complete the 2016 academic year.

The Faculty of Health Sciences will continue its classes and clinical rotations as normal for all three schools on the Bloemfontein Campus and in the relevant hospitals. All students registered in programmes in the Faculty of Health Sciences will stay in residences for the full period of their studies and exams. Final-year medical students will graduate in December 2016 as expected.
In the Faculty of Economic and Management Sciences, final-year students for the Certificate in the Theory of Accounting (CTA) will stay on campus during October through to December 2016 and their classes and tests will not change.
Arrangements for all other faculties and programmes are being prepared and within the next week, students and parents/guardians will receive communication about how curriculum content will be completed and when the final exams will take place.
The university is extending the academic year so that we can recuperate all the lost teaching and learning time. The qualifications conferred on the 2016 class will be of the same quality and standards as all UFS qualifications.

The UFS is and will remain a fundamentally contact teaching and learning education university. However, under the current circumstances faced not only by the UFS, but higher-education institutions across the country, the best way of ensuring the integrity of the academic programmes in most faculties is by using an alternative way of teaching and learning. Other South African universities have chosen the same approach to be able to complete the academic year.

Instead of students going to class, they will have content delivered to them where they are (library, computer labs, their own computers, etc.) through Blackboard and printed and electronic material. This is a different way of learning but students will be carefully guided and supported.

Faculties are currently preparing all the necessary materials and instructions to support student learning.Standards and quality will be the same as if students were attending classes. Some faculties require practical laboratory work as part of their curriculum. The exam timetable will be adapted for these students to be able to complete their practical work when the academic activities commences in November 2016. The relevant faculties will communicate the schedule of practical work directly to the students.

Students in their final year will complete their studies during 2016. It is possible that in some cases the graduation ceremony for these students will be in June 2017 instead of April 2017. This will not prejudice students with bursaries, or committed employment in law firms or other businesses. The university will provide the necessary academic transcripts as proof of the completion of the relevant qualifications. None of these changes will affect postgraduate students.

The university will maintain regular communication with students and parents/guardians to update them on the new exams timetable.Faculties will communicate directly with students about issues related to their programmes.

“One of the areas in which significant progress was made, is that we were able to agree on a basis for stability with student leaders. The student protests occurred during an important time in the university’s academic calendar and the readjustment of our academic programme has put tremendous pressure on academic and support services staff, and created anxieties for parents,” said Prof Nicky Morgan, Acting Rector of the UFS.

“The senior leadership restates its commitment to free education as well as its willingness to stand together with students and other public universities to impress on government the urgency to decide on a time frame for the roll-out of free higher education for the poor and missing middle. We will use the next two weeks to meet with the leadership of Universities South Africa to coordinate collective action in this regard. We will furthermore also roll out a series of activities to inform and educate students and the general public on different models and experiences of providing free higher education,” he said.

The strategy to readjust the 2016 academic year is applicable to students on the Bloemfontein and South Campuses.

Released by:
Lacea Loader (Director: Communication and Brand Management)
Telephone: +27 51 401 2584 | +27 83 645 2454
Email: news@ufs.ac.za | loaderl@ufs.ac.za
Fax: +27 51 444 6393

State of our campuses #15: UFS closes campuses until Friday 28 October 2016 to readjust academic programme

State of our campuses #14: All academic activities on UFS campuses remain suspended on 13 and 14 October 2016

State of our campuses #13: Availability of information about plans for remainder of UFS 2016 calendar year

State of our campuses #12: All academic activities at UFS campuses suspended for 11 and 12 October 2016

State of our campuses #11: Academic activities on UFS campuses continue

State of our campuses #10: Impact of non-completion of the 2016 academic year on UFS students

State of our campuses #9: Academic programme on all UFS campuses to resume on Monday 10 October 2016

State of our campuses #8: UFS extends vacation as from 28 September until 7 October 2016, 28 September 2016

State of our campuses #7: All three UFS campuses will be closed today, 27 September 2016.

State of our campuses #6: All UFS campuses reopen on Tuesday 27 September 2016

State of our campuses #5: UFS campuses to remain closed on Monday 26 September 2016

State of our campuses #4: Decisions about the UFS academic calendar

State of our campuses #3: UFS campuses closed until Friday 23 September 2016

State of our campuses #2: UFS Bloemfontein and South Campuses closed on Tuesday 20 September 2016 (19 September 2016)

State of our campuses #1: Academic activities suspended on UFS Bloemfontein Campus (19 September 2016)

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