Surely it would not be contested that the most effective measuring apparatus would simulate, as far as possible, the operation of placing concrete in typical conditions? The value of such a device would be considerably enhanced if additional information could be provided such as the ability of the concrete to flow, to compact fully, and to resist segregation. A method of satisfying these requirements would be to adopt an apparatus of the kind diagramed in the article. It comprises three items: a rectangular, heavy gage container of suitable size with two vertical channels at the midpoints on the inside of the longer sides; a screen, secured by removable clamps, made of round horizontal bars with openings between them of a size appropriate to the maximum size of aggregate in the mix under test; and a plate to act temporarily as a shutter during the placing of the sample of concrete in the compartment of the container. To determine the tendency of the mix to bleed and segregate, vibration would be resumed for as long as necessary to judge the stability of the mix. At the end point, bleed water would be removed and measured. The operator would also examine the condition of the top half-inch or inch or the compacted mix to observe any segregation that may have occurred. A further use would be to determine the build density of the mix.
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