2026-09-18T19:36:33Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/45395 2023-07-11 col_2142_5131 col_2142_14770 com_2142_5130 com_2142_3518 com_2142_234

Struble, Leslie J. Hunnicutt, William 2013-08-22T16:38:55Z 2013-08-22T16:38:55Z 2013-08 2013-08-22T16:38:55Z 2013-08 The primary objectives of this thesis were to synthesize calcium silicate hydrate (C-S-H) and calcium aluminosilicate hydrate (C-A-S-H) and characterize their structures with varying Ca/Si ratios and aluminum content. As a secondary objective, carbonation behavior in synthesized C-S-H was studied. C-S-H was synthesized in the lab using two different methods: the double decomposition of calcium nitrate and sodium silicate solutions, and the direct reaction between calcium oxide and fumed silica in water. In C-A-S-H the source of aluminum was sodium aluminate or aluminum nitrate. A variety of phases were present depending on the degree of carbonation of the C-S-H or C-A-S-H. C-S-H, C-A-S-H, alumina/silica gel, calcite, aragonite, and vaterite were all observed throughout the course of study. X-ray diffraction (XRD) was the technique used to identify these phases. XRD was also used to explore the changes in crystal structure with varying Ca/Si ratios and aluminum content. No significant changes to the crystal structure were found. The effect of Ca/Si ratio, aluminum content, and synthesis method were studied on the molecular scale using 29Si and 27Al nuclear magnetic resonance spectroscopy (NMR). An increasing Ca/Si ratio has the effect of a shorter alumino-silicate chain length and an increase in aluminum content increases the alumino-silicate chain length. Aluminum substitution occurred primarily in the bridging tetrahedron position, but also in the pairing tetrahedron position. Aluminum uptake was also examined with respect with Ca/Si ratio and was found to decrease with increasing Ca/Si ratio. The changes in chemical environment of the iii aluminum ion with varying Ca/(Si+Al) ratios was also observed by 27Al NMR. It was found that as the Ca/(Si+Al) ratio increased, the amount of chemical shielding of the 27Al nuclei decreased . Carbonation of C-S-H was also examined and it was found that the double decomposition synthesis method allows for more rapid carbonation of the CS- H. The source of increased carbonation rate is the high pH of the solutions. Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2013-07-16T18:55:20Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 4 MS Thesis_v4 with refs formatted v2.docx: 4766963 bytes, checksum: 1f97de3268cf062a5aca854ab9d732c8 (MD5) ABSTRACT and acknowledgements FINAL.docx: 20917 bytes, checksum: d013c4ae68fd3b33904c548b791656a3 (MD5) thesis title page.docx: 11979 bytes, checksum: 9b1cd0b9ef1f013c4b6523e627849fd5 (MD5) Hunnicutt_William.pdf: 4505955 bytes, checksum: 2a47e4bbf7226e54ad0830abac2e71f0 (MD5) Made available in DSpace on 2013-08-22T16:38:55Z (GMT). No. of bitstreams: 5 William_Hunnicutt.pdf: 4505955 bytes, checksum: 2a47e4bbf7226e54ad0830abac2e71f0 (MD5) MS Thesis_v4 with refs formatted v2.docx: 4766963 bytes, checksum: 1f97de3268cf062a5aca854ab9d732c8 (MD5) ABSTRACT and acknowledgements FINAL.docx: 20917 bytes, checksum: d013c4ae68fd3b33904c548b791656a3 (MD5) thesis title page.docx: 11979 bytes, checksum: 9b1cd0b9ef1f013c4b6523e627849fd5 (MD5) license.txt: 4067 bytes, checksum: f713eec48200f782e976911b3276c657 (MD5) http://hdl.handle.net/2142/45395 en Copyright 2013 William Hunnicutt calcium silicate hydrate (C-S-H) calcium aluminosilicate hydrate (C-A-S-H) nuclear magnetic resonance spectroscopy (NMR) Carbonation Ca/Si Characterization of calcium-silicate-hydrate and calcium-alumino-silicate-hydrate text Civil & Environmental Eng 1251 Civil Engineering 0106 University of Illinois at Urbana-Champaign Thesis M.S. MS:Civil Engineering -UIUC 10KS0106MS