Microwave-assisted selective demolition of concrete - Microwave-Assisted Concrete Technology: Production, Demolition and Recycling - page 91

deployed in practice, and the majority of the technologies reviewed require
further investigation to verify efficiency, effectiveness, as well as the actual
economic and environmental impacts when used as selective concrete demo-
lition tools. The selective demolition technologies available vary widely in
their effectiveness and processing rates. Except for demolition using chemi-
cal agents (expansive agents), other technologies discussed in the following
material rely mainly on the mechanical removal of concrete using cutting
and sawing equipment. As a result, most of the following methods share the
main disadvantages associated with mechanical-based methods, including
the associated health hazards and safety issues.
3.3.1 Pneumatic concrete breakers
Pneumatic breakers (Figure 3.3) are probably the most common type of
breakers for selective demolition in construction. In pneumatic breakers,
a pneumatic actuator is used to convert the compressed air's energy into
mechanical motion. The advantages of pneumatic breakers compared to
other available breakers include being relatively lightweight and inexpen-
sive. They are also considered long lasting and fairly easy to repair.
However, disadvantages include the requirement for fairly large air com-
pressor power sources, noise and dust hazards, and inoperability at low
temperatures. In addition, such air tools usually require a fair amount of
maintenance, including lubrication and the need to avoid moisture buildup
in lines. The use of breakers also poses health hazards caused by vibration.
Vibration is recognised to cause various health hazards, including blanch-
ing fingers under cold provocation, the so-called white fingers.
Figure 3.3 Handheld pneumatic breaker.