Microwave-assisted concrete recycling - Microwave-Assisted Concrete Technology: Production, Demolition and Recycling - page 163

(a) (b)

Figure 4.12 Microwave-assisted mortar separation equipment.

Before After

Figure 4.13 RCAs before and after microwave separation.

density of the RCAs treated. Microwave heating of air-dried RCA par-
ticles led to about 32% reduction in the mortar content and thereby 19%
reduction in the water absorption and 2.5% increase in the bulk density of
RCAs [31]. Additional rounds of microwave processing or an increase in
the microwave power and microwave heating duration can result in more
complete removal of the adhering mortar from RCA; however, it should
be noted that this may compromise the perceived economic and environ-
mental benefits derived; therefore, the optimal level of microwave heating
should be assessed prior to large-scale implementation.
The infrared thermal image of the RCAs taken immediately after the
microwave separation process is shown in Figure 4.14. As shown, the maxi-
mum temperature at the time of mortar fracture or detachment was less than