Later stages of Portland cement hydration influenced by different portions of silica fume, metakaolin and ground granula
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Later stages of Portland cement hydration influenced by different portions of silica fume, metakaolin and ground granulated blast‑furnace slag Eva Kuzielová1,2 · Matúš Žemlička1 · Martin Janča3 · Pavel Šiler3 · Martin T. Palou1,2,3 Received: 28 October 2019 / Accepted: 6 March 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract Two Portland cement (PC) replacement levels (35, 45 mass%) and three locally available supplementary cementitious materials (SCMs; metakaolin (MK, 5–15 mass%), silica fume (SF, 5, 10 mass%), ground granulated blast-furnace slag (BFS, 10–35 mass%)) in different ratios were used for the preparation of multicomponent binders, the hydration of which was studied up to 365 days by means of thermal analysis. The suitable compositions were found for both PC replacement levels. In the case of the lower one as well as in the compositions prepared with higher SF amount, 20 mass% of BFS appeared as beneficial. When lower amounts of SF and cement were used, samples with larger quantity of BFS reached better results. Concerning compressive strength (CS), synergic influence of SCMs overcame the dilution effect already after 28 days of curing and no significant dependence on the PC content was determined. Later, the majority of the blended samples reached higher CSs than the corresponding referential ones. With respect to the coefficient of pozzolanic activity, the combination of higher SF level (10 mass%) mainly with higher amount of BFS seemed to be more desirable in general. Keywords Multicomponent cements · Metakaolin · Silica fume · Ground granulated blast-furnace slag · Thermogravimetric analyses List of symbols C CaO S SiO2 A Al2O3 H H2O C̄ CO2
* Eva Kuzielová [email protected] 1
Institute of Construction and Architecture, Slovak Academy of Sciences, Dúbravská cesta 9, 845 03 Bratislava, Slovak Republic
2
Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovak Republic
3
Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic
Introduction The goal of the present as well as many other studies from the area of cement binders is ultimately to propose the possibilities how to reduce the amount of greenhouse gas emissions and achieve energy savings in cement production. Partial substitution of Portland clinker by supplementary cementitious materials (SCMs) belongs to the main possibilities how to achieve the requirements of the European Emission Trading Scheme Directive [1] as well as the economic ones [2]. Despite the plenty of investigated multicomponent cement systems and the related information available in the literature, still a lot of other work needs to be done. The first reason is the variety of local available SCMs, which should be used preferentially. For example, the availability of ground granulated blast-furnace slag and coal fly ashes, which currently belong to the most used SCMs, is limited to only about 20 mass% of global cement prod
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