PORTLAND CEMENT CONCRETE - Materials for Civil and Construction Engineers - page 246

FIGURE 7.3 Slump test

apparatus.

of water to the top surface of concrete). The slump test (Figure 7.3) is an in-
dicator of workability when evaluating similar mixtures. This test consists
of filling a truncated cone with concrete, removing the cone, then measur-
ing the distance the concrete slumps (ASTM C143). The slump is increased
by adding water, air entrainer, water reducer, superplasticizer, or by using
round aggregates. Table 7.7 provides recommendations for the slump of
concrete used in different types of projects. For batch adjustments, slump

T ABLE 7.7 Recommended Slumps for Various Types of Construction*

Slump, mm (in.)

Concrete Construction Maximum** Minimum

Reinforced foundation walls and footings 75 (3) 25 (1)

Plain footings, caissons, and substructure
walls 75 (3) 25 (1)

Beams and reinforced walls 100 (4) 25 (1)

Building columns 100 (4) 25 (1)

Pavements and slabs 75 (3) 25 (1)

Mass concrete 75 (3) 25 (1)

*American Concrete Institute (ACI 211.1).
**May be increased 25 mm (1 in.) for consolidation by hand methods such as
rodding and spading. Plasticizers can safely provide higher slumps.