electron microscopy; microstructure-final; spectroscopy; X-ray methods; cements; geopolymers
Abstract :
[en] Concurrently to research conducted on ordinary Portland cement (PC), new types of binders were developed during the last decades. These are formed by alkali-activation of metakaolin or ground-granulated blast furnace slag (GGBFS) and are named, respectively, geopolymers (GP) or alkali-activated slag (AAS). Four different cementitious materials were synthesised: PC, AAS, GP, and a mix GP-AAS and fully compared about their compositions and (micro)-structures. X-ray diffraction has revealed the presence of semi-crystalline C-S-H gel binding phase in PC while AAS, GP and GP-AAS are nearly amorphous. Progressive structural changes have been observed between the different samples by means of infrared spectroscopy, Si-29 and At-27 magic-angle-spinning nuclear magnetic resonance spectroscopy: there is a polymerisation extent of the (alumino)-silicate framework from PC [SiQ(1) and SiQ(2) units] to AAS [SiQ(2) and SiQ(2)(1Al) units] and finally to GP [SiQ(4)(2Al) and SiQ(4)(3Al) units]. Scanning electron microscopy has shown that GP is a homogeneous matrix while the other materials are composites containing GGBFS grains surrounded by a binding matrix. Energy dispersive X-ray EDX analyses (line scans) have shown the absence of formation of any specific phase at the matrix-grains interfaces. (c) 2006 Elsevier Ltd. All rights reserved.
Taylor H.F.W. Cement Chemistry (1990), Academic Press, London (United Kingdom)
Fernandez-Jimenez A., and Puertas F. Structure of calcium silicate hydrates formed in alkaline-activated slag: influence of the type of alkaline activator. J. Am. Ceram. Soc. 86 (2003) 1389
Schneider J., Cincotto M.A., and Panepucci H. 29Si and 27Al high-resolution NMR characterization of calcium silicate hydrate phases in activated blast-furnace slag pastes. Cem. Concr. Res. 31 (2001) 993
Richardson I.G., Brough A.R., Groves G.W., and Dobson C.M. The characterization of hardened alkali-activated blast-furnace slag pastes and the nature of the calcium silicate hydrate (C{single bond}S{single bond}H) phase. Cem. Concr. Res. 24 (1994) 813
Puertas F., Fernandez-Jimenez A., and Blanco-Varela M.T. Pore solution in alkali-activated slag cement pastes. Relation to the composition and structure of calcium silicate hydrate. Cem. Concr. Res. 34 (2004) 139
Wang S.-D., and Scrivener K.L. Hydration products of alkali activated slag cement. Cem. Concr. Res. 25 (1995) 561
Wang S.-D., and Scrivener K.L. 29Si and 27Al NMR study of alkali-activated slag. Cem. Concr. Res. 33 (2003) 769
Lecomte I., Liégeois M., Rulmont A., Cloots R., and Maseri F. Synthesis and characterization of new inorganic polymeric composites based on kaolin or white clay and on ground-granulated blast furnace slag. J. Mater. Res. 18 (2003) 2571
Davidovits, J., Chemistry of geopolymeric systems, terminology. In Géopolymère '99 Proceedings, Saint-Quentin, France, 1999, p. 9.
Barbosa V.F.F., Mackensie K.J.D., and Thaumaturgo C. Synthesis and characterisation of materials based on inorganic polymers of alumina and silica: sodium polysialate polymers. Int. J. Inorg. Mater. 2 (2000) 309
Taylor H.F.W. Proposed structure for calcium silicate hydrate gel. J. Am. Ceram. Soc. 69 (1986) 464
Lequeux N., Morau A., Philippot S., and Boch P. Extended X-ray absorption fine structure investigation of calcium silicate hydrates. J. Am. Ceram. Soc. 82 (1999) 1299
Cong X., and Kirkpatrick R.J. 29Si MAS NMR study of the structure of calcium silicate hydrate. Adv. Cem. Bas. Mater. 3 (1996) 144
Yu P., Kirkpatrick R.J., Poe B., McMillan P.F., and Cong X. Structure of calcium silicate hydrate (C{single bond}S{single bond}H): near-, mid-, and far-infrared spectroscopy. J. Am. Ceram. Soc. 82 (1999) 742
Mollah M.Y.A., Lu F., and Cocke D.L. An X-ray diffraction (XRD) and Fourier transform infrared spectroscopic (FT-IR) characterization of the speciation of arsenic(V) in Portland cement type-V. Sci. Total Environ. 224 (1998) 57
Hanna R.A., Barrie P.J., Cheeseman C.R., Hills C.D., Buchler P.M., and Perry R. Solid state 29Si and 27Al NMR and FTIR study of cement pastes containing industrial wastes and organics. Cem. Concr. Res. 25 (1995) 1435
Clayden N.J., Esposito S., Aronne A., and Pernice P. Solid state 27Al NMR and FTIR study of lanthanum aluminosilicate glasses. J. Non-Cryst. Solids 258 (1999) 11
Handke M., and Mozgawa W. Vibrational spectroscopy of the amorphous silicates. Vib. Spectrosc. 5 (1993) 75
Sitarz M., Handke M., and Mozgawa W. Identification of silicooxygen rings in SiO2 based on IR spectra. Spectrochim. Acta Part A 56 (2000) 1819
Swainson I.P., Dove M.T., and Palmer D.C. Infrared and Raman spectroscopy studies of the α-β phase transition in cristobalite. Phys. Chem. Miner. 30 (2003) 353
Lippmaa E., Samoson A., and Mägi M. High-resolution 27Al NMR of aluminosilicates. J. Am. Chem. Soc. 108 (1986) 1730
Thomas J.M., and Klinowski J. The study of aluminosilicate and related catalysts by high-resolution solid-state NMR spectroscopy. Adv. Catal. 33 (1985) 199
Andersen M.D., Jakobsen H.J., and Skibsted J. Incorporation of aluminium in the calcium silicate hydrate (C{single bond}S{single bond}H) of hydrated Portland cements: A high-field 27Al and 29Si MAS NMR investigation. Inorg. Chem. 42 (2003) 2280
Skibsted J., Henderson E., and Jakobsen H.J. Characterization of calcium aluminate phases in cements by 27Al MAS NMR spectroscopy. Inorg. Chem. 32 (1993) 1013
Richardson I.G., Brough A.R., Brydson R., Groves G.W., and Dobson C.M. Location of aluminium in substituted calcium silicate hydrate (C{single bond}S{single bond}H) gels as determined by 29Si and 27Al NMR and EELS. J. Am. Ceram. Soc. 76 (1993) 2285