Solid state 29Si MAS NMR is a versatile spectroscopic technique to study anisotropic interactions of Si in geopolymeric cement systems. This article is concerned with the analysis of structural information and mechanism for evolution of tailored geopolymeric precursor powder originated after mechanical co-grinding of fly ash, NaOH and amorphous tricalcium phosphate. The solid state 29Si MAS NMR of geopolymeric precursor material shows distinguishable chemical shifts. Results indicated that developed geopolymeric precursor contain Si/Al tetrahedral network in which SiQ4(3-4Al) dominated among Q0, Q1 and Q2. The evolution of green phosphatic geopolymer cement material takes place after addition of water to developed precursor material. Results also provide an insight about -Si-O-Si- interactions in geopolymer precursor formation, due to reorganization and structural disordering, as a noteworthy greener solid state mechanism. Another eminent finding of this study is the occurrence of significant change in chemical shift values caused by grinding. These shifts are accompanied by incorporation of Al in Si-O-Si linkages and 3D crosslinking into the matrix in geopolymeric precursor material itself, leading to formation of transient Si/Al containing species following solid state mechanism.
Tailored geopolymeric precursor Geopolymeric cement Greener solid state mechanism Chemical shift
This is a preview of subscription content, log in to check access.
The authors would like to thanks Director CSIR-AMPRI for motivating the research work. Thanks are also due to Dr. Rajamohan, CSIR-National Chemical Laboratory, Pune, Maharashtra, India for providing 29Si NMR experimentation facility.
Compliance with Ethical Standards
Conflict of Interests
Authors of this research declare no conflicts of interest.
Brus J, Abbrent S, Kobera L, Urbanova M, Cuba P (2016) Advances in 27Al MAS NMR studies of Geopolymers. Annu Rep NMR Spectrosc 88:79–147CrossRefGoogle Scholar
Wang SH, DePaul SM, Bull LM (1997) High-resolution heteronuclear correlation between quadrupolar and spin-1/2 nuclei using multiple-quantum magic-angle spinning. J magnetic. Resonance 125:364–368CrossRefGoogle Scholar
Fernandez C, Lang DP, Amoureux JP, Pruski M (1998) Measurement of heteronuclear dipolar interactions between quadrupolar and spin-1/2 nuclei in solids by multiple quantum REDOR NMR. J American. Chem Soc 120:2672–2673CrossRefGoogle Scholar
Maciel GE, Sindorf DW (1980) Silicon-29 nuclear magnetic resonance study of the surface of silica gel by cross polarization and magic angle spinning. J American Chem Soc 102:7606–7607CrossRefGoogle Scholar
Palomo A, Grutzeck MW, Blanco MT (1999) Alkali activated fly ashes- a cement for the future. Cem Concr Res 29(8):1323–1329CrossRefGoogle Scholar
Engelhardt G, Hoebbel D (1984) 29Si N.M.R. spectroscopy reveals dynamic SiO4(4_) group exchange between silicate anions in aqueous alkaline silicate solutions. J the chemical society. Chem Commun 514–517Google Scholar
Mattias E (2012) NMR studies of oxide-based glasses. Annual reports on the Progress of chemistry section C Phys. Chemistry 108:177–221Google Scholar
Singh PS, Trigg M, Burgar I, Bastow T (2005) Geopolymer formation processes at room temperature studied by 29Si and 27Al MAS-NMR. Mater Sci Eng A 396:392–402CrossRefGoogle Scholar
Nasab GM, Golestanifard F, MacKenzie KJD (2014) The effect of the SiO2/Na2O ratio in the structural modification of metakaolinbased geopolymers studied by XRD, FTIR and MAS-NMR. J Ceram. Sci Technol 05(03):185–192Google Scholar
Phair JW, Van Deventer JSJ (2002) Effect of the silicate activator pH on the microstructural characteristics of waste-based geopolymers. Int J Miner Process 66:121–143CrossRefGoogle Scholar
Sahai N, Tossell JA (2001) Formation energies and NMR chemical shifts calculated for putative serine-silicate complexes in silica biomineralization. Geochim Cosmochim Acta 65(13):2043–2053CrossRefGoogle Scholar
Duxson P, Provis JL, Lukey GC, Separovic F, van Deventer JSJ (2005) Si-29 NMRstudy of structural ordering in aluminosilicate geopolymer gels. Langmuir 21:3028–3036CrossRefPubMedGoogle Scholar
Škvára F, Kopecký L, Nemecek J, Bittnar Z (2006) Microstructure of geopolymer materials based on flyash. Ceramics–silikáty 50(4):208–215Google Scholar
Gupta R, Bhardwaj P, Deshmukh K, Mishra D, Prasad M, Amritphale SS (2018) Development and characterization of inorganic-organic (Si-O-Al) hybrid Geopolymeric precursors via solid state method. SILICON. https://doi.org/10.1007/s12633-018-9847-7
Gupta R, Bhardwaj P, Mishra D, Mudgal M, Chouhan RK, Prasad M, Amritphale SS (2017) Evolution of advanced Geopolymeric cementitious material via novel process. Adv Cem Res 29(3):125–134CrossRefGoogle Scholar
Tsai YL, Hanna JV, Lee YL, Smith ME, Chan JCC (2010) Solid-state NMR study of geopolymer prepared by sol–gel chemistry. J Solid State Chem 183:3017–3022CrossRefGoogle Scholar
Palomo A, Alonso S, AF J’n (2004) Alkaline activation of Fly ashes: NMR study of the reaction products. J the Amer Chem Soc 87(6):1141–1145Google Scholar
Sturm P, Greiser S, Gluth GJG, Jager C, Brouwers HJH (2015) Degree of reaction and phase content of silica-based one-part geopolymers investigated using chemical and NMR spectroscopic methods. J Mater Sci 50:6768–6778CrossRefGoogle Scholar