PROMOTING SUSTAINABLE CONSTRUCTION in AFRICA
The provision of infrastructure such as bridges and roads is fundamental to economic development in West Africa. However, high temperatures, high humidity, the coastal climate along the main transport routes, and regular flooding in this region pose serious threats to such assets. Their failure would have serious economic consequences in Ghana and its neighbouring countries. MC-Bauchemie is developing and testing application-oriented decision-making aids and innovative building materials designed to also benefit the local value chains in the maintenance and repair of infrastructure assets.
MC-Bauchemie is involved in the German-Ghanaian INFRACOST project, which is funded by the German Federal Ministry of Education and Research (BMBF) as part of the “CLIENT II - International Partnerships for Sustainable Innovation” initiative. In short, INFRACOST is about adapting concrete infrastructure and the built environment in Ghana to ecological challenges and risks, and ensuring that the associated structures can be maintained on a sustainable footing. It evaluates the structural condition of system-relevant infrastructure assets and develops maintenance concepts that can ensure their continued functional integrity.
INFRACOST is a joint project in which MC-Bauchemie works together with various project partners. While the Federal Institute for Materials Research and Testing (BAM) is investigating and evaluating the use of local raw materials together with the University of Ghana, MC-Bauchemie Ghana is developing and testing application-oriented decision-making aids and innovative building materials designed to also benefit the local Ghanaian value chains in the maintenance and repair of infrastructure assets. Also involved in this project is an array of other partners such as local universities, trade associations and governmental agencies. Now in its fourth year, the project is managed by Dr. Wolfram Schmidt of the BAM.
Local solutions to global problems
The focus is on developing concretes optimised for increased life expectancy for new build projects, together with structurally strengthening mortars for repair and refurbishment work. To make the respective technologies more sustainable, the INFRACOST project consortium is developing them primarily on the basis of locally available raw materials, including organic and mineral by-products from other processes. In Ghana, agricultural residues such as cassava peels and waste from cocoa production have a particularly important role to play in this respect.
Since knowledge and technology transfer are also essential elements of this project, INFRACOST promotes and provides university courses not just for students but also for industrial company and public authority personnel, as well as practical training for users and planners. Moreover, a handbook for advisers and political decision-makers has also been developed to provide key guidance and recommendations.
To cement and consolidate the process of knowledge transfer, the research results and technologies have been directly applied as part of a pilot repair campaign involving the Saglemi Bridge in cooperation with the Ghana Highway Authority. Looking forward, it is expected that the project will give a significant boost to improving Ghana’s infrastructure.
For further information, please go to: https://www.bmbf-client.de
Interview with Dr.-Ing. Wolfram Schmidt
Dr. Wolfram Schmidt from the Department of Building Materials Technology of the BAM (see below) is widely experienced in international research cooperation. The building materials technologist is currently coordinating the INFRACOST project in Ghana funded by the Federal Ministry of Education and Research (BMBF). We talked to him about the opportunities and requirements for more ecologically compatible construction within the African market.
Africa is a growing continent with huge potential. Looking to the future, how – in your opinion – is the construction sector there likely to develop in the coming decades?
The best prospects for economic development in growing African cities derive from the ensuing enormous demand for building materials. So far only 20 per cent of the urban structures destined to be built by 2050 have actually been constructed. Conversely, that means that 80 per cent of the city buildings that the future holds are likely to be constructed over the next 30 years. Without concrete, that will not be possible. Even though it is considered unpopular, in the absence of economic alternatives it remains the most suitable building material for the African cities of the future. Compared to all other building materials, including steel, it has the lowest carbon footprint and energy input requirement. Timber is expensive, scarce and deforestation is causing dramatic environmental damage in many African countries. So concrete is the only building material on earth that can meet this enormous global demand driving construction.
How is this huge demand for concrete – and therefore for cement – as a building material going to be satisfied?
One option is through previously unused agricultural residues from the region. These contain mineral components that are suitable as binder substitutes, as well as organic constituents that can serve to improve robustness or as liquefying admixtures in the concrete. Such options could contribute to sustainability and the reduction of climate emissions in two ways: firstly by reducing cement consumption and secondly by making better use of the cement used. The most likely resource for cement replacement here is ash from agricultural waste. This occurs in large quantities and is not currently being used for other technologies. When agricultural waste is burned at temperatures between 600 and 800 °C, the residual ash will often contain significant amounts of reactive silica and aluminium oxides, enabling it to replace up to 30 per cent or more of the Portland cement clinker used in concrete, a commodity that commands an appreciably higher price on the trading markets. Before the ash is produced, organic components can be extracted which improve concrete processability. Indeed, such low-cement concretes cannot be manufactured without them, as the ashes produced often exhibit a higher water demand and can in some cases significantly change the overall binder system. Superplasticisers and stabilisers are the key to success here, which means the expertise of the construction chemicals industry is also very much in demand.
Producing climate-friendly concretes does indeed appear to be a highly innovative and sustainable approach! Where do you see the obstacles to market implementation arising?
The biggest hurdle to the extensive utilisation of such green building materials lies in society’s misconception that agricultural waste products are only suitable for low-end use.
So it is imperative that future decision-makers in rural areas be made aware of the opportunities and acquire a clear conception of the economic and social potential of agro-based building material markets. In addition to new sources of income, these markets also help to strengthen regional agriculture, making it more secure and enhancing its independence. It is a win-win situation, with agricultural waste products combining with construction chemical admixtures to produce a climate-friendly concrete – to the benefit of both local populations and the construction industry at large.
The Federal Institute for Materials Research and Testing (BAM) is a scientific and technical higher federal authority assigned to the Federal Ministry for Economic Affairs and Energy. It tests, researches and advises on the protection of people, the environment, materials and manufactures, while serving to maintain high health and safety standards in technology and chemistry covering Germany and its global markets. As such, it contributes to the further enhancement of Germany’s culture of quality under the “Made in Germany” brand.
For further information, please go to: https://www.bam.de