TY - JOUR
T1 - Relating the nano-mechanical response and qualitative chemical maps of multi-component ultra-high performance cementitious binders
AU - Ford, Emily L.
AU - Hoover, Christian G.
AU - Mobasher, Barzin
AU - Neithalath, Narayanan
N1 - Funding Information:
This study was partly supported by U.S. National Science Foundation ( CMMI : 1463646 ) and Arizona Department of Transportation (ADOT: SPR745 ). The first author acknowledges a Dean’s Fellowship from Arizona State University . The authors would like to thank Alejandro Bonilla of Applied Nanosolutions for sharing his AFM expertise and Omar Albor Castillo for his assistance in post-processing the nanoindentation data.
Funding Information:
This study was partly supported by U.S. National Science Foundation (CMMI: 1463646) and Arizona Department of Transportation (ADOT: SPR745). The first author acknowledges a Dean's Fellowship from Arizona State University. The authors would like to thank Alejandro Bonilla of Applied Nanosolutions for sharing his AFM expertise and Omar Albor Castillo for his assistance in post-processing the nanoindentation data.
Publisher Copyright:
© 2020 Elsevier Ltd
PY - 2020/11/10
Y1 - 2020/11/10
N2 - Ultra-high performance (UHP) cement pastes with 30–50% of cement (by mass) replaced by multiple cement replacement materials are evaluated in this study through concise nanomechanical investigations and qualitative chemical intensity mapping. Nanomechanical clustering identifies high density (HD) C-S-H and an ultra-high stiffness (UHS) phase as the major reaction products in very low w/b UHP pastes. Chemical mapping revealed HD C-S-H and UHS phases to have similar mean Ca and Si intensities. The indentation modulus (M) - hardness (H) relationships for the C-S-H phases in the UHP pastes are similar irrespective of their starting compositions. The mean Ca/(Si + Al) intensity ratio is found to be lower for the UHS phase, and the Al incorporation is noted to be higher. The Al incorporation in the C-A-S-H gel is seen to depend more on the Ca/Si ratio of the gel rather than on the amount of Al in the starting materials. The normalized chemical intensities and ratios of Ca, Si, and Al species, along with the mechanical property description provided by nanoindentation, allows for further insights into the microstructure of complex, heterogeneous systems such as UHPC pastes.
AB - Ultra-high performance (UHP) cement pastes with 30–50% of cement (by mass) replaced by multiple cement replacement materials are evaluated in this study through concise nanomechanical investigations and qualitative chemical intensity mapping. Nanomechanical clustering identifies high density (HD) C-S-H and an ultra-high stiffness (UHS) phase as the major reaction products in very low w/b UHP pastes. Chemical mapping revealed HD C-S-H and UHS phases to have similar mean Ca and Si intensities. The indentation modulus (M) - hardness (H) relationships for the C-S-H phases in the UHP pastes are similar irrespective of their starting compositions. The mean Ca/(Si + Al) intensity ratio is found to be lower for the UHS phase, and the Al incorporation is noted to be higher. The Al incorporation in the C-A-S-H gel is seen to depend more on the Ca/Si ratio of the gel rather than on the amount of Al in the starting materials. The normalized chemical intensities and ratios of Ca, Si, and Al species, along with the mechanical property description provided by nanoindentation, allows for further insights into the microstructure of complex, heterogeneous systems such as UHPC pastes.
KW - C-S-H
KW - Chemical mapping
KW - Energy Dispersive X-Ray Spectroscopy (EDS)
KW - Nanoindentation
KW - Ultra-high performance concrete (UHPC)
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U2 - 10.1016/j.conbuildmat.2020.119959
DO - 10.1016/j.conbuildmat.2020.119959
M3 - Article
AN - SCOPUS:85086883124
SN - 0950-0618
VL - 260
JO - Construction and Building Materials
JF - Construction and Building Materials
M1 - 119959
ER -