Project Details
Projekt
R-ClinkerControl: AI augmented control model for coping with fluctuating recycling waste in carbonate-melt clinkering for recycling-cement
Subject Area
Construction Material Sciences, Chemistry, Building Physics
Term
since 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 541857967
The ecological footprint of (Portland) cement is dominated by process and energy related emissions resulting from the extremely high temperatures needed in the clinkering process. The proposed research addresses both of these levers: It focuses on novel recycling cement clinker (R-clinker) with a lime-module of approx. 2 - and thus low process emissions - and a strongly reduced processing temperature below 1000 °C. Instead of using limestone marl, crushed concrete fines (which are rich in hardened cement paste (hcp) and can thus provide CaO without detrimental CO2 emissions) as clinker raw meal substitute are to be studied. As these fines highly fluctuate in their compositions, in depth understanding not only of the clinkering process using such fines, but also on the technical properties of the resulting clinker has to be gained. In doing so a machine learning control model is to be elaborated, which not only predicts the R-clinker (technical) properties, but also proposes countermeasures in case of raw meal fluctuations. In the clinkering process, new synthesis pathways based on carbonate melts are to be investigated, allowing to further reduce the clinkering temperature as well as the C/S-ratio of the raw meal necessary for the clinkering process. Such reduced temperatures also open pathways for increasing the reactivity of belite, formed in this process. The carbonate melt pathway is especially important when using crushed concrete fines as raw meal, as the C/S-ratio of the latter is normally too low for clinker synthesis. The lack of CaO in the raw meal will thus be compensated by CaCO3 addition, inevitably leading to process related CO2 emissions, which however help to form the carbonate melts. In a second funding phase (FP II), it is intended to extend the carbonate-melt process with a rapid carbonation step of the non-fines fraction of recycled concrete, which possesses ecologically important contents of hcp available for CO2-binding. Instead of having to employ energy and CO2-intensive Carbon-Capture techniques, the emitted process CO2 emissions in the carbonate-melt clinkering process proposed in this research can thus be directly sequestrated by carbonating the remaining recyclate fractions, thus potentially being net zero. In funding phase FP I, the research will focus on studying the effect of the strongly varying elemental composition and physical properties (i e porosity) of recycled type II concrete fines onto the clinkering process as well as on the technical properties of the resulting R-clinker. The process data will be coupled with investigations on the technical performance of the resulting clinkers, s. a. rheological properties, strength development, deformation behavior, durability) as to yield in a holistic, AI augmented control model for R-clinker synthesis, which will also incorporate sustainability aspects such as emissions and resources consumption as well as technical properties such as durability.
DFG Programme
Priority Programmes
Subproject of
SPP 2436:
Net-Zero Concrete
Co-Investigators
Dr. Corinna Rozanski; Dr. Angela Ullrich
