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Search Publications by: Andrew J Allen (Fed)

Displaying 126 - 131 of 131

The Surface Area of Cement Paste as Measured by Neutron Scattering -- Evidence for Two C-S-H Morphologies

October 1, 1998

Author(s)

J Thomas, Hamlin M. Jennings, Andrew J. Allen

Small-angle neutron scattering was used to measure the effect of water-to-cement ratio [w/c] and cement batch variation on the surface area of ordinary Portland cement [opc] paste after hydration for 28 days at room temperature, and to measure the

Multiple Small-Angle Neutron Scattering

September 1, 1998

Author(s)

Gabrielle G. Long, Susan Krueger, Andrew J. Allen

Over the past decade, a multiple small-angle neutron scattering (MSANS) formalism has been developed to enable researchers to derive microstructural parameters from multiply-scattered small-angle neutron data. The MSANS formalism is particularly useful in

Determination of the Neutron Scattering Contrast of Hydrated Portland Cement Paste Using H 2 0/D 2 0

June 1, 1998

Author(s)

J Thomas, Hamlin M. Jennings, Andrew J. Allen

Accurate measurements of the surface area of cement based materials using small-angle neutron scattering (SANS) require determination of the neutron scattering contrast between the C-S-H gel and H6d2^O. Because the C-S-H gel has a poorly understood

Anisotropic Microstructure of Plasma-Sprayed Deposits

April 1, 1998

Author(s)

J Ilavsky, Gabrielle G. Long, Andrew J. Allen, L Leblanc, M Prystay, C Moreau, Alan H. Band

The microstructure of plasma-sprayed deposits [PSD] is dominated by two void systems-interlamellar pores and intralamellar cracks - each with a different anisotropy. Varying anisotropies and crack-to-pore ratios within PSDs are responsible for the

USAXS Studies of Silica Fume Additives in Cements and Concrete

April 1, 1998

Author(s)

Andrew J. Allen, Richard A. Livingston

Supplementary cementitious materials like silica fume, which are added to the cement mix and react with calcium ions in the pore solution, enhance the production of calcium-silicate-hydrate gel and modify the microstructure in other ways. By combining

Evolution of the Microstructure of Plasma-Sprayed Deposits During Heating

January 1, 1998

Author(s)

Gabrielle G. Long, Andrew J. Allen, J Ilavsky

The evolution of the void microstructure of yttria-stabilized zirconia [YSZ] plasma-sprayed deposits [PSD] was studied as a function of heating in air from room temperature to 1400 C, and during a constant temperature hold at 1100 C for 19 hours. The