TY - JOUR
T1 - Mesoscale texture of cement hydrates
AU - Ioannidou, Katerina
AU - Krakowiak, Konrad J.
AU - Bauchy, Mathieu
AU - Hoover, Christian G.
AU - Masoero, Enrico
AU - Yip, Sidney
AU - Ulm, Franz Josef
AU - Levitz, Pierre
AU - Pellenq, Roland J.M.
AU - Del Gado, Emanuela
N1 - Funding Information:
This work is supported by Schlumberger under the Cement under Extreme Conditions Project and the Concrete Sustainability Hub at Massachusetts Institute of Technology. E.D.G. acknowledges support from Swiss National Science Foundation Grant PP00P2_150738 and National Science Foundation Grant NSF PHY11-25915. This work has been carried out within the framework of ICoME2 Labex Project ANR-11-LABX- 0053 and A*MIDEX Project ANR-11-IDEX-0001-02 cofunded by the French program Investissements d''Avenir, which is managed by the French National Research Agency.
PY - 2016/2/23
Y1 - 2016/2/23
N2 - Strength and other mechanical properties of cement and concrete rely upon the formation of calcium-silicate-hydrates (C-S-H) during cement hydration. Controlling structure and properties of the C-S-H phase is a challenge, due to the complexity of this hydration product and of the mechanisms that drive its precipitation from the ionic solution upon dissolution of cement grains in water. Departing from traditional models mostly focused on length scales above the micrometer, recent research addressed the molecular structure of C-S-H. However, small-angle neutron scattering, electron- microscopy imaging, and nanoindentation experiments suggest that its mesoscale organization, extending over hundreds of nanometers, may be more important. Here we unveil the C-S-H mesoscale texture, a crucial step to connect the fundamental scales to the macroscale of engineering properties. We use simulations that combine information of the nanoscale building units of C-S-H and their effective interactions, obtained from atomistic simulations and experiments, into a statistical physics framework for aggregating nanoparticles. We compute small-angle scattering intensities, pore size distributions, specific surface area, local densities, indentation modulus, and hardness of the material, providing quantitative understanding of different experimental investigations. Our results provide insight into how the heterogeneities developed during the early stages of hydration persist in the structure of C-S-H and impact the mechanical performance of the hardened cement paste. Unraveling such links in cement hydrates can be groundbreaking and controlling them can be the key to smarter mix designs of cementitious materials.
AB - Strength and other mechanical properties of cement and concrete rely upon the formation of calcium-silicate-hydrates (C-S-H) during cement hydration. Controlling structure and properties of the C-S-H phase is a challenge, due to the complexity of this hydration product and of the mechanisms that drive its precipitation from the ionic solution upon dissolution of cement grains in water. Departing from traditional models mostly focused on length scales above the micrometer, recent research addressed the molecular structure of C-S-H. However, small-angle neutron scattering, electron- microscopy imaging, and nanoindentation experiments suggest that its mesoscale organization, extending over hundreds of nanometers, may be more important. Here we unveil the C-S-H mesoscale texture, a crucial step to connect the fundamental scales to the macroscale of engineering properties. We use simulations that combine information of the nanoscale building units of C-S-H and their effective interactions, obtained from atomistic simulations and experiments, into a statistical physics framework for aggregating nanoparticles. We compute small-angle scattering intensities, pore size distributions, specific surface area, local densities, indentation modulus, and hardness of the material, providing quantitative understanding of different experimental investigations. Our results provide insight into how the heterogeneities developed during the early stages of hydration persist in the structure of C-S-H and impact the mechanical performance of the hardened cement paste. Unraveling such links in cement hydrates can be groundbreaking and controlling them can be the key to smarter mix designs of cementitious materials.
KW - Cement
KW - Mechanics
KW - Mesoscale
KW - Microstructure
KW - Simulations
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U2 - 10.1073/pnas.1520487113
DO - 10.1073/pnas.1520487113
M3 - Article
AN - SCOPUS:84959230265
SN - 0027-8424
VL - 113
SP - 2029
EP - 2034
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 8
ER -