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- Titel:
Accelerated carbonation hardening of binders based on raw dolomite – a way to a new resource-efficient construction material with low CO2 footprint.
- Dokumenttyp:
- Konferenzbeitrag
- Art des Konferenzbeitrags:
- Poster
- Autor(en):
- Stoklosa, Agnieszka; Hilbig, Harald; Machner, Alisa
- Abstract:
- Raw dolomite (< 90 wt.% dolomite) is one of the most abundant mineral resources. However, its widespread availability is underutilized due to the presence of impurities. In many technical applications, the high purity requirements for dolomite make raw dolomite unsuitable for direct use in numerous processes. This project contributes to the priority program SPP 2436 Net-Zero Concrete, which encompasses various projects focused on reducing the CO₂ footprint and resource consumption of cement and concrete production. The goal of the project is to gain a better understanding of the hydration and carbonation processes in a carbon-neutral binder system based on raw dolomite. This approach offers significant potential for developing climate-friendly construction materials, as dolomite calcination requires lower temperatures compared to those needed for synthesizing clinker phases in Portland cement. Our preliminary experiments showed that samples containing reactive MgO and CaO phases achieved better compressive strength compared to slaked lime samples when exposed to a CO2-rich environment. Therefore, we will integrate carbon capture and utilization (CCU) strategies and establish a closed-loop CO2 cycle. In the first phase of this project, an appropriate raw dolomite will be selected. At least one pure and one impure type of raw dolomite will be required. The materials will be characterized using methods such as Thermogravimetric analysis (TGA), X-ray Diffraction (XRD), and Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). In the next step, the raw dolomite will be calcined. Various calcination regimes, including temperatures ranging from 600 to 900 °C and durations of 1 to 6 hours, will be tested. The effect of these calcination regimes on the phase development will be examined, along with the mutual impact of the process and secondary constituents. Subsequently, the reactivity of the calcined dolomite will be assessed, focusing on the reactivity of MgO and CaO. Most reactive samples will then be prepared for carbonation hardening. For this purpose, calcined and slaked dolomite will be mixed with water (water-to-binder ratio (w/b) of 0.3–0.5) and aggregates (quarzitic sand, limestone, or dolomite). Finally, the samples will be carbonated in a carbonation chamber and high-pressure reactors under various conditions: pressures of 1–50 bar, temperatures of 20–50 °C, and durations of 4–24 hours. On the carbonated samples we will perform compressive and flexural strength tests. A multi-analytical approach will provide information on how carbonation parameters affect phase formation (Ca and Mg carbonates, amorphous gel), microstructure development, porosity, and strength. Additionally, the effect of different aggregates on phase formation, microstructure, and strength will be evaluated. In this contribution, we will present the first results from the early phase of this project.
- Stichworte:
- raw dolomite; magnesium binder; calcination; carbonation
- Kongress- / Buchtitel:
- 5th International Conference on the Chemistry of Construction Materials (5th ICCCM)
- Datum der Konferenz:
- 8.-10.09.2025
- Jahr:
- 2025
- Reviewed:
- nein
- Sprache:
- en
- TUM Einrichtung:
- Centrum Baustoffe und Materialprüfung; Professur für Mineral Construction Materials; TUM School of Engineering and Design; cbm Baustoffinstitut
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