HANDLING AND TRANSPORTING
When ready-mixed concrete is carried by an
ordinary type of carrier (such as a wheelbarrow or
buggy), jolting of the carrier increases the natural
tendency of the concrete to segregate. Carriers
should therefore be equipped with pneumatic tires
whenever possible, and the surface over which they
travel should be as smooth as possible.
A long free fall also causes concrete to segregate.
If the concrete must be discharged at a level more than
4 feet above the level of placement, it should be
dumped into an elephant trunk similar to the one
shown in figure 6-7.
Segregation also occurs when discharged
concrete is allowed to glance off a surface, such as the
side of a form or chute. Wheelbarrows, buggies, and
conveyors should discharge so that the concrete falls
Concrete should be transported by chute only for
short distances. It tends to segregate and dry out
when handled in this manner. For a mix of average
workability y, the best slope for a chute is about 1 foot
of rise to 2 or 3 feet of run. A steeper slope causes
segregation, whereas a flatter slope causes the
concrete to run slowly or not at all. The stiffer the
mix, the steeper the slope required. All chutes and
spouting used in concrete pours should be clean and
well-supported by proper bracing and guys.
Figure 6-7.-Chute, or downpipe used to check free fall of concrete.