Kinshasa, june 22nd, 2025 (CPA).– The use of ‘calcined clay-limestone’ mixtures as a partial substitute for clinker in the manufacture of ‘Portland composite cement’ was analyzed on Saturday during the defense of a doctoral thesis at the University of Kinshasa (UNIKIN) in the Democratic Republic of Congo (DRC).
« Through our study on the use of calcined clay-limestone mixtures, we have introduced new materials to replace the main product in cement manufacturing. This cement, produced using sustainable methods, is proving to be an advantageous alternative for many megaprojects, particularly in construction, » said Guyghens Bongwele, head of research and author of the thesis at the UNIKIN Faculty of Science and Technology. In this thesis entitled ‘Use of calcined clay-limestone/dolomitic limestone mixtures from Songololo as a partial substitute for clinker in the manufacture of Portland cement (Central Kongo, DRC),’ the recipient pointed out that this less expensive substitute offers more effective solutions in terms of resistance to stress and sulphates, as well as reducing CO2 emissions. According to him, the choice of subject for this doctoral thesis should not be underestimated, as the challenges of reducing CO2 emissions and combating global warming are more relevant than ever.
Mr Bongwele said in his presentation that major projects such as Inga (the Inga hydroelectric dam on the Congo River in the DRC) and the challenges associated with the increased cost of cement for consumers require immediate attention. ‘Producing sulphate-resistant cement with low CO2 emissions meets urgent and contemporary needs, thus justifying this innovation,’ he argued. The author also encouraged the country’s authorities to quickly put into practice the results of his research on the use of this cement in industrial processes. ‘Knowing the methods of production of these materials, it is crucial to start using them without delay,’ he recommended. Calcined clay is clay that has been heated to a high temperature (between 650°C and 750°C), which alters its structure and properties. It is used as a substitute for cement, particularly in the production of concrete. This doctoral thesis earned him a Doctor of Science degree with ‘high distinction.’