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1/6 Fresh concrete
Table 1.1 Common single-point workability tests
Test Principle Comments
Slump (Figure 1.1) measures a flow property of • suitable for medium and high workability concrete
concrete under self-weight • sensitive to small changes in water content
after standard compaction • very simple, suitable for site use
• heavily operator dependent
Compacting measures the effect of a
factor standard amount of work • suitable for low, medium and high
(Figure 1.2) (height of fall) on compaction workability mixes
Vebe measures the amount of work • fairly simple, but requires scales
(Figure 1.3) (time at constant vibration) • less operator dependent than slump
for full compaction
• suitable for very low and low workability mixes
Flow table measures the effect of a • greater relation to concrete placing
(Figure 1.4) standard amount of work
(bumps) on spread conditions than slump
Slump flow • more complex than other methods, requires
(Figure 1.5) as in the slump test, measures
a flow property of concrete standard vibrating equipment
Degree of under self-weight, but after • sometimes difficult to define end point
compactability self-weight compaction
(Figure 1.6) • suitable for high and very high workability
measures the effect of a mixes
standard amount of work
(dropping the concrete from • gives some indication of tendency of mix to segregate
the edge of the container) on • fairly simple, but, like slump, operator dependent
compaction
• developed for self-compacting concrete
• very simple, suitable for site use
• operator dependent, but less so than slump
• an alternative to the compacting factor test
• simple, suitable for site use
• likely to be operator dependent
100 Slump: British and European
300 standards
American
standard
200 2. The cone is slowly 3. The slump is
raised and the measured using the
1. The cone is filled with concrete is allowed to upturned cone and
concrete in three equal slump under its own slump rod as a
layers, and each layer is weight. guide
compacted with twenty-five
tamps of the tamping rod.
True Shear Collapse
Types of slump
Figure 1.1 The slump test (BS 1881 Part 102: 1983; BS EN 12350-2: 2000; ASTM C 143-90a).
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