Microwave-assisted selective demolition of concrete - Microwave-Assisted Concrete Technology: Production, Demolition and Recycling - page 87

Microwave- assisted selective
demolition of concrete
3.1 INTRODUCTION
Partial removal of concrete and drilling into concrete are inevitable in many
retrofitting, repair, restoration, and deconstruction projects. However,
because of the considerably high toughness of concrete, it is usually dif-
ficult to demolish or drill into a particular section of concrete components
without causing damage to the surrounding concrete. Selective demolition
of concrete using conventional tools, including chisels and hammers, pneu-
matic breakers, and hydraulic breakers, poses considerable health hazards
to the equipment operators, building occupants, and other affected indi-
viduals because of the relatively high amount of noise, dust, and vibration
generated during the demolition process. Heightened awareness about the
social element of sustainability in construction has highlighted the neces-
sity of eliminating possible causes of health hazards in construction sites as
well as reducing the noise and dust pollution caused by construction activi-
ties. The inevitable tightening of safety and health standards together with
the constant push for efficiency in the construction industry have motivated
a number of researchers to seek alternative selective demolition techniques
for concrete. The recent advances in technology have opened up a variety
of technological options to develop new selective demolition techniques
for concrete with reduced noise and dust generation, through avoiding
mechanical collisions and improved removal rates.
This chapter looks into applications of microwave heating in the selective
demolition and drilling of concrete. The chapter starts by reviewing a num-
ber of commonly encountered situations for which the use of more efficient
selective demolition tools (e.g., microwave removal and drilling) can make
a difference. It then continues by reviewing the designs and working prin-
ciples of a number of potential selective demolition tools proposed in the
available literature and describes the typical components of such tools. The
focus is placed on microwave-assisted selective demolition and microwave-
assisted drilling methods as alternatives to the existing selective demoli-
tion and drilling methods for concrete. The results of a numerical study
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