The density increases and porosity decreases
from BA40 to BA70. The density depends mostly on the pore structure,
which resulted from the release of gas during microwave irradiation.
With the bottomash percentage increasing and sodiumsilicate percentage
decreasing, the amount of pores decreases. So, the bulk density of
samples increases with the bottom ash percentage. The sample BA40
shows the lowest bulk density of 0.61 g/cm3 and the highest porosity
at 72% whereas sample BA70 shows the highest bulk density at
1.3 g/cm3 and the lowest porosity of 41%. The result of porosity was in
good agreement with that of bulk density