The global cement production and utilization for manufacturing concrete amounts to an estimated 5 to 8% of the CO2 emissions worldwide (Danyang Cheng, et al., 2023). In the third quarter of 2021, Kenya’s civil engineering industry consumed about 2.596 metric tons of cement, burdening the climate with an CO2 equivalent emission amounting to at least 1.2 million tons in those years. These emissions mostly result from production of Portland cement clinker, where CaCO3 has to be reduced to CaO, which account for approximately 60% of the grey CO2 from cement. The Meru University of Science and Technology (MUST) studied opportunities to reduce these emissions and is part of the Limestone Calcined Clay Cement (LC3) project. At the same time the Bundesanstalt für Materialforschung und Prüfung (BAM ) has successfully worked on processing and implementing bio-based natural pozzolana to replace fossil resource-based supplements like cementitious materials, including fly ash and silica fume in Nigeria and Ghana since 2018 (Schmidt, et al., 2024) (Schmidt W, Commeh M, Olonade K, Schiewer, GL, 2021). To date clinker in Kenya is largely replaced by fly ash, a byproduct of fossil coal combustion, which, however, has to be imported. According to the enterprise Volza Grow Global, Kenya was importing fly ash from 70 countries in the past years , which not only has an enormous car¬bon footprint, but also costs the national economy valuable currency. Given the carbon footprint for the fly ash’s transport it is more than desirable to reduce the CO2 equivalent emissions in alternative ways (Paul S. Fennell, Steven J. Davis, & Aseel Mohammed, 2021).

Therefore, this research aims at replacing educts for the cement production taking into consideration the Kenyan situation, with smaller and a more local circularity, also with the objective to stimulate the local economy and society. This way, out of biomass, input for clinker importation should be reduced on a reliable basis, so satisfying the civil engineering quality requirements e.g. strength and durability. Up to now, the imported fly ash with a high price, is barely covering the needs for Kenya’s input. The MUST, BAM and SRH consortium is researching the CO2 footprint reduction in the coming four years on a Kenyan, East African and Pan-African level . In order to produce pozzolanic ash indigenously in Kenya, relevant biomass is identified, its seasonal availability charted, and the in¬volvement of sources and value chains studied. Part of this research is the mineral availability in the respective biomass, whereby two groups of biomasses are considered. Excluded are growing trees, given the important CO2 sequestration function vis-à-vis the climate change, which includes mostly healthy trees. Conditionally considered are also biomass, that carry a value for the populations and are already part of a value chain. Instead, the scope is waste biomass and invasive biomass species, for which the ten most relevant species are identified and sorted by appropriate criteria. Out of these, horticulture alone makes up to 12 million tons in 2022. For the purpose of left over material husks, cobs or pruning that regularly occur, could be used. In terms of invasive species, carbonizing and ashing might help regain control over water hyacinths, mesquite or other aggressive weeds and the collateral damage they cause. This way, materials like pruning are going to be sampled, their ash content measured, and the composition of their ashes determined. Hereby the seasonal changes are going to be considered. Similarly, invasive species such as Mesquite are going to be consi¬dered, given their abundant availability and hindrance of populations and economic activity. The metho¬dology involves a systematic review of literature, a field study and the analysis of the results with assis¬tance from AI systems and algorithms. AI is going to be indicating apparent results early on, and so contributing to an efficient international cooperation between the three research institutions. Outcome of this research is contributing to significantly reduce the CO2 footprint of the cement industry in countries, until CO2 is captured (CCS), and in a fashion that large proportions of the population can be sustainably involved in their generation of income.