pouring in hot bitumen is quite common in colder climates.
cement is a great filler! and cheap!
the greek and turkish fishermen used to use pine resin with sawdust added,but these days sikaflex is so much easier.
in east africa
coconut coir,limestone powder ,coconut oil
is used for caulking,then overcoated with tar.
in the carbbean,polystyrene melted with petrol makes a paste that can be used as a filler,
also in west africa
,but with fibers from baobab tree seed pods crushed added