It might be possible to melt concrete if lava in contact with it was hot enough. But it is more likely that concrete would decompose and become "crumbly" before it "melted" when heated.
yes it can
Lava.
The ingredients of lava are, melted rock and fossils
"lava"
lava
If it reaches the surface, it is magma or lava. If it merely intrudes into rocks already formed, it is intrusive. Such as sills and dikes.
Lava.
Fast moving-melted lava.
The ingredients of lava are, melted rock and fossils
Chocolate lava is just melted chocolate.
Lava
"lava"
Lava is melted rock, it is quite viscous.
Lava.
lava
Lava.
Lava.
lava