Similarly, the iron industry aims at using alternative renewable fuel sources for its manufacturing process, which means that the composition and quality and probably also the amount of blast furnace slag will be affected. The German environmental goals target the closing of coal power plants by the year 2038, which means the available amount of fly ash from local sources in Germany will decrease in some years. However, the environmental protection laws in many countries and European environmental goals aim to reduce and eventually omit the burning of coal and encourage renewable energies. Several publications have shown the potential of granulated blast furnace slag and fly ash as a precursor for AAB/GP. Moreover, the type and concentration of alkaline solution impact the reactivity of the aluminosilicate precursors used for AAB/GP. ![]() On the other hand, such large variations in the precursor composition make it difficult to draw general valid rules to synthesize these binders with the expected properties. On the one hand, the wide variety of precursors available for the synthesis of AAB/GP makes them a suitable alternative binder for many applications. However, the nature, chemical and mineralogical composition of the aluminosilicate precursor affect the properties of the resultant binder, such as fresh and hardened characteristics. Natural or artificial pozzolans, including granulated blast furnace slag, fly ash, metakaolin, or natural pozzolans, can be used as aluminosilicate sources. ĪAB/GP are synthesized by the reaction of an aluminosilicate precursor with an alkaline source. Alkali-activated binders (AAB) and/or geopolymers (GP) omit the energy-intensive kiln process that is responsible for a large part of the CO 2 emissions of conventional types of cement and therefore are considered as environmentally friendly alternatives. However, exploring more CO 2-friendly alternatives requires an extensive experimental program and, consequently, long development cycles until they can be used in practice. In this regard, the cement technology roadmap defined several ways to reduce the CO 2 footprint at every step of cement production and huge afford has been made to develop more environmentally friendly binders. If the climate agreements are adhered to, the question arises as to what extent ordinary Portland cement (OPC) as a building material is still viable as a mass product. The increasing demand for infrastructure development throughout the globe related to increasing population and consequently economic growth leads to continued high consumption of cement-based building materials. Since the cement is the most important constituent of concrete and its production is associated with the emission of CO 2, around eight percent of man-made CO 2 emissions come from the production of cement. In 2019 alone, worldwide 30 billion tons of concrete was produced-that is almost four tons for every single person. This brings applications in laboratory practice within reach.Ĭoncrete is the most widely used building material on earth. The results show the advantage of SL, i.e., the amount of data required can potentially be reduced by at least one order of magnitude compared to traditional machine learning models, while at the same time exploiting highly complex information. The influence of some constraints was systematically analyzed, e.g., the possibility to parallelize the experiments, the influence of the chosen algorithm and the size of the training data set. The success is benchmarked in terms of the number of experiments required to find materials with the desired strength. The sought-after target property is the compressive strength of the binders after 28 days. The data sources are described in detail, and the differences between the binders are discussed. For this purpose, 131 data points were collected from different publications. ![]() The SL approach combines machine learning models and feedback from real experiments. This work adopts sequential learning (SL) in high-dimensional material spaces (consisting of composition and processing data) to find AABs that exhibit desired properties. However, as yet there are no sufficiently accurate material models to effectively predict the AAB properties, thus making optimal mix design highly costly and reducing the attractiveness of such binders. Alkali-activated binders (AAB) can provide a clean alternative to conventional cement in terms of CO 2 emissions.
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