Hydration of high alumina cement–silica fume composite with addition of Portland cement or sodium polyphosphate under hydrothermal treatment

• Published in: Journal of thermal analysis and calorimetry 2013-07, Vol.113 (1), p.385-394
• Main Authors: Palou, Martin T., Bágeľ, Ľubomír, Živica, Vladimír, Kuliffayová, Marta, Ifka, Tomáš
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Analytical Chemistry; Applied sciences; Binders; Buildings. Public works; Calcium carbonate; Cement; Cement concrete constituents; Cements; Chemistry; Chemistry and Materials Science; Curing; Exact sciences and technology; Hydration; Inorganic Chemistry; Materials; Measurement Science and Instrumentation; Physical Chemistry; Polymer Sciences; Polyphosphates; Properties of anhydrous and hydrated cement, test methods; Silica; Sodium; Thermal analysis
• ISSN: 1388-6150; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-013-3042-2

Various hydrothermal curing regimes were used to investigate the hydration and physical characteristics of two kinds of inorganic binder composites: high alumina cement–silica fume–Portland cement and high alumina cement–silica fume–sodium polyphosphate. Simultaneous thermal analysis (DTA and TG) was used to identify temperature ranges of thermal decomposition of cured samples and to characterize the nature of hydrate products. Two kinds of products are formed. The first ones consist of C 3 AH 6 , AH 3 , calcium carbonate (C–C) as a product of carbonation, and C 3 AH 1.5 resulted from the partial decomposition of C 3 AH 6 under higher hydrothermal pressure. The second ones are the products formed by acid–base reaction between monocalcium aluminate and sodium polyphosphate to form NaCaPO 4 · x H 2 O and Al 2 O 3 · x H 2 O that could convert to chemically bonded ceramic binders like hydroxyapatite (Ca 5 (PO 4 ) 3 OH) and gibbsite (Al(OH) 3 ). These two hydroceramic products formed under these conditions act also as binder and could be useful as cement binders for the protection of petroleum, gas, or geothermal wells. Mercury intrusion porosimeter was used for the estimation of the pore structure parameters of the composites. It turned up that longer curing time coupled with higher hydrothermal pressure has improved the pore structure of the first composite, while that of the second has remained unchanged.