The rheological properties of a suspension of lime in water (lime putty) are studied with the help of creep tests in a wide range of deformations including very small values. The results are compared with those obtained with a cement paste and several similarities between the two systems are observed. It is shown that the apparent yield stress of a lime suspension is the sum of two components: one due to standard reversible colloidal interactions and one due to the formation of a brittle structure associated with the formation of links due to dissolution-precipitation mechanisms. This second component increases with the time of rest as the square root of time, and the corresponding structure irreversibly breaks as soon as some significant deformation has been imposed. We show that similar structures are formed at concentrations between 25 and 34 % (solid volume fraction) and evolve in a similar way when the time is scaled by a factor decreasing with the solid fraction.
We show that it is possible to follow the liquid transfer between a cement paste and a porous medium in contact with it, by analyzing the evolution of the distribution of 1 H NMR relaxation times. This in particular makes it possible to see that whatever the initial water fraction in the paste, a porous medium with sufficiently small pores can rapidly extract a significant amount of water from this paste. Afterwards, during the hydration process, the cement paste progressively gets water back from this porous medium. The amount of water thus extracted by the paste finally appears to just compensate the volume loss due to water consumption by the hydration process.
Lead thioarsenate glasses are promising materials for a number of potential applications in far infrared optics, chemical sensing, nonlinear photonics, etc. Electronic properties of the PbS-As 2 S 3 glasses were studied in the past, however, the relationship between the glass and crystal characteristics have not been established. Here we compare the glass-forming domain in the pseudo-binary system obtained by usual melt-quenching and mechanical milling. Macroscopic and electrical glass properties are analyzed in comparison with their crystalline counterparts: PbAs 2 S 4 , Pb 5 As 9 S 18 , and Pb 2 As 2 S 5 , and the annealed glasses yielding glassy/crystalline alloys. Although the primary crystallization phases in glasses are consistent with the phase diagram, the lead local environment seems to be different in glasses and crystals, reflected by their properties and preliminary high-energy X-ray diffraction results.
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