Setting Kinetics of High-dispersed Refractory Castables

Dana Jahn1, Olaf Krause2, Daniel Cölle3, Holger Schaffhauser3

1 Forschungsgemeinschaft Feuerfest e. V. 53113 Bonn/Germany
2 University of Applied Science, FH-Koblenz, 56203 Höhr-Grenzhausen/Germany
3 EKW GmbH, 67304 Eisenberg/Germany


Volume 4, Issue 4, Pages 81 - 88


It is well-known that the hardening behaviour of cementous systems essentially depends on the mineralogy of the cement type and the interactions between cement particles and related additives. With aspects to characteristically applied installation techniques of refractory castables, this fact emphasizes the assumption that different combinations of dispersing agents or plasticizers, which are based on polycarboxylateether (PCE) technology with commercially available calciumaluminatecements (CAC) lead to a variety of hardening profiles which also effects their drying behaviour. The presented study combines the results obtained by applying simultaneous measurement devices, named sonic velocity and electrical conductivity, over the first 48 h after casting and conventional measurement of the mechanical strength after defined hardening time intervals. Additional XRD measurements accomplished for a selection of pure cement slurries-additive combinations give a clear indication that the mineralogy of the cement hydrate phases reacts sensitively, when different dispersing agents are used. Over fifty different combinations of refractory castable compositions of the type low cement castable (LCC) were evaluated. A representative selection is envisaged. Although all applied cements show roughly equal chemical compositions, with an alumina content of 70 mass-%, the setting time varies within a wide time range: between 8 and more than 48 h – to be precise. Despite the mineralogy of the CAC, the characteristic relationship between setting kinetics and strength evolution is obviously essential controlled by the applied dispersing agents.


refractory castables, polycarboxylateether, calciumaluminatecements


[1] Brunder, R.; Meinig, J.: Trocknen, Anheizen, Aufund Abheizen, in: Feuerfestbau: Werkstoffe – Konstruktion – Ausführung. 3rd Ed. Essen 2003, 317–326

[2] Parr, C.; et al.: Optimization of the hardening properties of refractory castables using nondestructive techniques to measure early age properties. Int. J. of Appl. Ceram. Technol. 4 (2007) [6] 524–534

[3] Cardoso, F.A.; et al.: Effect of curing conditions on the properties of ultra-low cement refractory castables. Refractories Applications and News 9 (2004) [2] 12–16

[4] Salomao, R.; Ismael, M.R.; Pandolfelli, V.C.: Hydraulic binders for refractory castables: Mixing, curing and drying. cfi/Ber. DKG 84 (2007) [9] E102–E108

[5] Krause, O.; et al.: Development of monitoring tools to assist the drying of monolithic refractory materials. Proc. of Unitecr’09, Salvador de Bahia 2009, on CD (not paginated)

[6] Parr, C.; Wöhrmeyer, C.: A new insight into the matrix interactions of deflocculated castables which control placing and setting properties. Proc. of Unitecr’07, Dresden 2007, 405–408

[7] Götz-Neunhoeffer, F.: Modelle zur Kinetik der Hydratation von Calciumaluminatzement mit Calciumsulfat aus kristallchemischer und mineralogischer Sicht. Habilitationsschrift 2006, Erlanger Forschungen, Reihe B, Naturwissenschaften und Medizin, Band 29

[8] Parr, C.: The impact of calcium aluminate cement hydration upon the properties of refractory castables. Technical paper ref. No. TP-GB-RELAF- 043, 2004,

[9] Möhmel, S.: Die Reaktionen von Calciumaluminaten bei Hydratation und thermischer Belastung – Beiträge zur Chemie der Hochtonerdezemente. Habilitationsschrift 2002. Technische Universität Bergakademie Freiberg 2003

[10] Cölle, D.: Untersuchungen zur Abbindekinetik selbstfließender Feuerbetone unter Anwendung eines Ultraschallmesssystems. Keram. Z. 54 (2002) 660–662

[11] Dinger, D.R.: Mixing. Ceramic Processing E-zine (2007),

[12] Krause, O.; Cölle, D.; Jahn, D.; Schaffhauser, H.: Hardening kinetics of refractory castables in terms of varying cement and dispersing agents with reference to the expected drying behaviour. Proc. of XVII. Int. Conf. on Refractories, Prague 2011, 95–98


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