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Nanoglobule stability in C-S-H gel in Portland cement
Fractal strength of cement samples Portland cement is the most important hydraulic binder used in current building practice. Its main hydration product – calcium silicate hydrate (C-S-H gel) – is a dominant compound of all cement and concrete materials. It is believed that the microstructure of this solid gel considerably influences all macroscopic mechanical properties of hydrated cement materials but so far any concept quantifying this influence has not been found. The objective of the present research consits in developing such a concept. The research is focused on experimental verification of a quantitative relation between macroscopic strength and fractal dimension of the microscopic gel porosity. Such a relation may bring benefits for non-destructive testing of this widely-used building material.
In order to verify the relation between mechanical strength and fractal dimension of the nanostructure of the cement gel, 24 samples have been measured by using SANS technique. Their strength was determined separately by means of independent mechanical experiments at domestic laboratory. Since the strength with this material varies with water-to-cement ratio, the series of 24 samples consisted of groups with the different ratios 0.4, 0.6, 0.8, 1.0, 1.2, 1.4. Each group was represented by 4 samples.
The user (TF) is grateful to the Resposible Operator, Dr. Adel Len, for her considerable support and kind assistance. Thanks are also due to Dr. Laszlo Almasy (BNC) for preliminary tests.
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Experiment at Budapest Neutron Center.
Supported by the EU through FP5, FP6 and FP7