INVESTIGATION OF A VIBRATING SLOPE METHOD FOR MEASURING CONCRETE WORKABILITY.
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
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The investigation consisted of a series of test designed to evaluate a method of determining the workability of freshly mixed concrete using a vibrating, sloping trough. In this test method, a given weight of concrete is consolidated in a container at the upper end of the sloping trough or channel. The wall at the lower end of the container is then removed, and the whole assembly is vibrated. The time required for half of the initial weight of the concrete to flow down the channel under vibration is used as a measure of the workability. The less the time required for the half-weight to deposit on a scale at the end of the channel, the more workable is the mixture. The slope test indicated a difference in workability of mixtures with identical slumps, but proportioned to be different in consistency. The test is applicable to mixtures with maximum size aggregates up to 6 in. For slump variation of 14 in., the slope time variation was approximately 10 sec. Results of tests performed as part of another program indicated that variation in air content, with slump and mortar volume constant, has little effect on workability as determined by the vibrating slope method. The information derived from this investigation indicated that the vibrating slope apparatus can be used as a relatively simple measure of the workability of concrete. Author
- Ceramics, Refractories and Glass
- Test Facilities, Equipment and Methods