Chemical and Physical Properties of the Nanoscale Building Blocks of Concrete A.J. Allen, J.J. Thomas and H.M. Jennings; Nature Materials, 6, 311 (2007). Using NSF-funded instruments at the NIST Center for High Resolution Neutron Scattering (CHRNS), scientists have made important new discoveries regarding a key component of one of the most prolific manufactured materials, Portland cement concrete. The key component, known as calcium-silicate-hydrate (C-S- H) gel, is produced when cement is hydrated (mixed with water). It binds the agglomerate, giving concrete its strength. The composition and density of solid C-S-H is notoriously difficult to obtain due to its A nanometer (nm) is one-billionth of a meter. Calcium silicate Bound water Surface water Free water 5 nm uncertain water content under different humidity conditions. Combining neutron and x-ray measurements, small angle scattering was used to determine, for the ﬁrst time without recourse to drying, the composition and density of C-S-H in its native state. The figure schematically shows the nanoscale structure of C-S-H particles in the gel. The results of this work have implications for a better understanding of the properties of concrete such as its response to mechanical loads and changes in temperature and humidity. Dan Neumann, National Institute of Standards and Technology, DMR 0454672

Chemical and Physical Properties of the Nanoscale Building Blocks of Concrete

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Calcium silicate. A nanometer (nm) is one-billionth of a meter. Bound water. Surface water. Free water. 5 nm. Chemical and Physical Properties of the Nanoscale Building Blocks of Concrete. Dan Neumann, National Institute of Standards and Technology, DMR 0454672. - PowerPoint PPT Presentation

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Chemical and Physical Properties of the Nanoscale Building Blocks of Concrete

A.J. Allen, J.J. Thomas and H.M. Jennings; Nature Materials, 6, 311 (2007).

Using NSF-funded instruments at the NIST Center for High Resolution Neutron Scattering (CHRNS), scientists have made important new discoveries regarding a key component of one of the most prolific manufactured materials, Portland cement concrete. The key component, known as calcium-silicate-hydrate (C-S-H) gel, is produced when cement is hydrated (mixed with water). It binds the agglomerate, giving concrete its strength. The composition and density of solid C-S-H is notoriously difficult to obtain due to its

A nanometer (nm) is one-billionth of a meter.

Calcium silicate

Bound water

Surface water

Free water

5 nmuncertain water content under different humidity conditions.Combining neutron and x-ray measurements, small angle scattering was used to determine, for the first time without recourse to drying, the composition and density of C-S-H in its native state. The figure schematically shows the nanoscale structure of C-S-H particles in the gel. The results of this work have implications for a better understanding of the properties of concrete such as its response to mechanical loads and changes in temperature and humidity.

Dan Neumann, National Institute of Standards and Technology, DMR 0454672