TY - JOUR
T1 - Sodium silicate activated slag-fly ash binders
T2 - Part III—Composition of soft gel and calorimetry
AU - Sankar, Kaushik
AU - Stynoski, Peter
AU - Kriven, Waltraud M.
N1 - The authors thank Dr. Andre Sutrisno of the School of Chemical Sciences NMR Laboratory for help in setting up, analysis and discussion of the MAS-NMR data. The authors also thank Dr. Xu Chen for discussions on selective chemical extractions and spectral subtractions of MAS-NMR data. The authors gratefully acknowledge the help provided by Prof. John S. Popovics, Mr. Dipobrato Sarbapalli, and Mr. Sang Min Lee of the Department of Civil and Environmental Engineering at UIUC for access, training, and discussions relating to SUWR. The authors are grateful for the funding provided by the US Army Construction Engineering Research Laboratory (USACE ERDC-CERL). The authors also thank Mr. Matthew Landi for help in performing the Penetration testing at CERL.
The authors thank Dr. Andre Sutrisno of the School of Chemical Sciences NMR Laboratory for help in setting up, analysis and discussion of the MAS‐NMR data. The authors also thank Dr. Xu Chen for discussions on selective chemical extractions and spectral subtractions of MAS‐ NMR data. The authors gratefully acknowledge the help provided by Prof. John S. Popovics, Mr. Dipobrato Sarba-palli, and Mr. Sang Min Lee of the Department of Civil and Environmental Engineering at UIUC for access, training, and discussions relating to SUWR. The authors are grateful for the funding provided by the US Army Construction Engineering Research Laboratory (USACE ERDC‐CERL). The authors also thank Mr. Matthew Landi for help in performing the Penetration testing at CERL.
PY - 2019/6
Y1 - 2019/6
N2 - Sodium silicate activated, slag-fly ash binders are potential alternative binders to Portland cement. In this study, the early age properties of slag-fly ash binders namely, set time, and heats of reaction were investigated. Set time was investigated using a combination of two methods namely, the ASTM C403 penetration testing, and s-wave ultrasonic wave reflectometry (SUWR). The discrepancy in set time identified by these two methods suggested the presence of a soft gel which eventually hardened with time. The composition of this soft gel was analyzed by suspending the chemical reaction of the binder after the soft gel formed, but before it hardened. In order to analyze the composition of the soft gel, selective chemical extractions were performed on the binder. 29 Si Magic Angle Spinning-Nuclear Magnetic Resonance (MAS-NMR), and FTIR spectroscopy were performed on binders and extraction residues. The soft gel contained a modified calcium silicate hydrate gel (C–N–S–H where N=Na), with a short mean chain length and no observable Al incorporation. Orthosilicate units were also found to be present in relatively high proportions when compared to hardened binders at later ages.
AB - Sodium silicate activated, slag-fly ash binders are potential alternative binders to Portland cement. In this study, the early age properties of slag-fly ash binders namely, set time, and heats of reaction were investigated. Set time was investigated using a combination of two methods namely, the ASTM C403 penetration testing, and s-wave ultrasonic wave reflectometry (SUWR). The discrepancy in set time identified by these two methods suggested the presence of a soft gel which eventually hardened with time. The composition of this soft gel was analyzed by suspending the chemical reaction of the binder after the soft gel formed, but before it hardened. In order to analyze the composition of the soft gel, selective chemical extractions were performed on the binder. 29 Si Magic Angle Spinning-Nuclear Magnetic Resonance (MAS-NMR), and FTIR spectroscopy were performed on binders and extraction residues. The soft gel contained a modified calcium silicate hydrate gel (C–N–S–H where N=Na), with a short mean chain length and no observable Al incorporation. Orthosilicate units were also found to be present in relatively high proportions when compared to hardened binders at later ages.
UR - https://www.scopus.com/pages/publications/85057755880
UR - https://www.scopus.com/pages/publications/85057755880#tab=citedBy
U2 - 10.1111/jace.16219
DO - 10.1111/jace.16219
M3 - Article
AN - SCOPUS:85057755880
SN - 0002-7820
VL - 102
SP - 3175
EP - 3190
JO - Journal of the American Ceramic Society
JF - Journal of the American Ceramic Society
IS - 6
ER -