caa a22 4500 463189876 CHVBK 20180406164905.0 cr unu---uuuuu 170326e20071201xx s 000 0 eng 10.1007/s10973-007-8517-6 doi (NATIONALLICENCE)springer-10.1007/s10973-007-8517-6 Degree of hydration in cement paste and C3A-sodium carbonate-water systems [Elektronische Daten] [I. Janotka, S. Mojumdar] This research provides a fundamental understanding of the early stage hydration of Portland cement paste, tricalcium aluminate (C3A) paste at water to cement ratio of 0.5 and C3A suspension at water to cement ratio of 5.0 modified by 2 or 4 mass% of sodium carbonate. A high conversion of unreacted clinker minerals to gel-like hydration products in the cement-Na2CO3 pastes takes place rapidly between 1st to 24th h. Contrary the Ca(OH)2 formation within the same time interval is retarded in the excess of CO 3 2− ions due to intensive rise and growth of CaCO3 crystals in hydrated cement. Later, the conversion of clinker minerals to the hydrate phase is reduced and higher contents of calcite and vaterite relative to that of Ca(OH)2 in comparison with those found in the Portland cement paste are observed. As a consequence a decrease in strength and an increase in porosity between hardened Portland cement paste without sodium carbonate and those modified by Na2CO3 are observed. C3A hydrates very quickly with sodium carbonate between 1st and 24th h forming hydration products rich in bound water and characterized also by complex salts of (x)C3A·(y)CO2·(zH2O type, whereas C3A-H2O system offers C3AH6 as the main hydration product. Higher content of the formed calcium aluminate hydrates in C3A-Na2CO3-H2O system also contributes to early strength increase of Portland cement paste. Springer Science+Business Media, LLC., 2007 C3A suspension nationallicence cement paste nationallicence hydration nationallicence porosity nationallicence strength nationallicence Janotka I. Institute of Construction and Architecture, Slovak Academy of Sciences, Dúbravská 9, 845 03, Bratislava 45, Slovakia aut Mojumdar S. Department of Chemical Engineering, University of Waterloo, 200 University Ave. West, N2L 3G1, Waterloo, ON, Canada aut Journal of Thermal Analysis and Calorimetry Springer US; http://www.springer-ny.com 90/3(2007-12-01), 645-652 1388-6150 90:3<645 2007 90 10973 https://doi.org/10.1007/s10973-007-8517-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10973-007-8517-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Janotka I. Institute of Construction and Architecture, Slovak Academy of Sciences, Dúbravská 9, 845 03, Bratislava 45, Slovakia aut NATIONALLICENCE 700 1- Mojumdar S. Department of Chemical Engineering, University of Waterloo, 200 University Ave. West, N2L 3G1, Waterloo, ON, Canada aut NATIONALLICENCE 773 0- Journal of Thermal Analysis and Calorimetry Springer US; http://www.springer-ny.com 90/3(2007-12-01), 645-652 1388-6150 90:3<645 2007 90 10973 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer