caa a22 4500 46319246X CHVBK 20180406164913.0 cr unu---uuuuu 170326e20070101xx s 000 0 eng 10.1007/s10973-006-7840-7 doi (NATIONALLICENCE)springer-10.1007/s10973-006-7840-7 Gradualtransformation of Ca(OH)2 into CaCO3on cement hydration [Elektronische Daten] XRD study [Ewa Stepkowska, M. Aviles, J. Blanes, J. Perez-Rodriguez] The low temperature of decomposition of some calcium carbonates and the bending of the TG curves of hydrated cement between 500 and 800°C suggested the presence of some complex compound(s), which needed complementary investigation (XRD, TG). Stepwise transformation of portlandite (and/or lime) into calcium carbonate, with intermediate steps of calcium carbonate hydroxide hydrates (CCH-1 to CCH-5), was indicated by the previous study of two OPC. This was checked here on four cements ground for t g=15, 20, 25 and 30 min and hydrated either in water vapour, successively at RH=1.0, 0.95 and 0.5 for 2 weeks each (WR1, WR2 and WR3, respectively) or as mortars in liquid water (1m), followed by WR as above. The d[001] spacing of portlandite was confirmed to vary: here between the lowest and the highest standard values. The diffractograms of n=32 different samples were analyzed for presence of standard CCH peaks, generally slightly displaced. These were: CCH-1 [Ca3(CO3)2(OH)2]: N=11 peaks, of three different d[hkl] spacings, CCH-2 [Ca6(CO2.65)2(OH657)7(H2O)2]: N=10 for two d[hkl], CCH-3 [Ca3(CO3)2(OH)2·1.5H2O]: N=14 for five d[hkl], CCH-4, ikaite [CaCO3(H2O)6]: N=13 for six d[hkl], CCH-5[CaCO3(H2O)]: N=15 for five d[hkl]. Thus the most probable is the presence of the last three. The stepwise transformation of Ca(OH)2 into CaCO3 was confirmed: portlandite (varying d[001])→CCH-1→CCH-2→CCH-3→CCH-4→CCH-5→CaCO3 The content of CCH was the highest at t gr=15 min, decreasing down to t gr=25 min and increasing slightly at 30 min, as inferred from the number of the peaks observed. After cement powder hydration at RH=1.0 (WR1) peak number increased gradually from CCH-1 to CCH-5, whereas in the hydrated mortar (1m) the peak number decreased from CCH-1 to CCH-5, indicating the respective progress of the carbonation reaction. Springer-Verlag, 2007 calcium carbonates nationallicence calcium carbonates hydrates nationallicence calcium carbonate hydroxide nationallicence carbonation of portlandite nationallicence cement grinding nationallicence cement hydration nationallicence XRD nationallicence Stepkowska Ewa Institute of Hydro-Engineering PAS, 80-953, Gdańsk, Poland aut Aviles M. Instituto de Ciencia de Materiales de Sevilla CSIC, 41 092, Sevilla, Spain aut Blanes J. Instituto de Ciencia de Materiales de Sevilla CSIC, 41 092, Sevilla, Spain aut Perez-Rodriguez J. Instituto de Ciencia de Materiales de Sevilla CSIC, 41 092, Sevilla, Spain aut Journal of Thermal Analysis and Calorimetry Kluwer Academic Publishers 87/1(2007-01-01), 189-198 1388-6150 87:1<189 2007 87 10973 https://doi.org/10.1007/s10973-006-7840-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10973-006-7840-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Stepkowska Ewa Institute of Hydro-Engineering PAS, 80-953, Gdańsk, Poland aut NATIONALLICENCE 700 1- Aviles M. Instituto de Ciencia de Materiales de Sevilla CSIC, 41 092, Sevilla, Spain aut NATIONALLICENCE 700 1- Blanes J. Instituto de Ciencia de Materiales de Sevilla CSIC, 41 092, Sevilla, Spain aut NATIONALLICENCE 700 1- Perez-Rodriguez J. Instituto de Ciencia de Materiales de Sevilla CSIC, 41 092, Sevilla, Spain aut NATIONALLICENCE 773 0- Journal of Thermal Analysis and Calorimetry Kluwer Academic Publishers 87/1(2007-01-01), 189-198 1388-6150 87:1<189 2007 87 10973 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer