Cover with solid pace, injecting velocity to avert century (4)
I believe the answer is:
pave
'cover with solid' is the definition.
I don't understand how the rest of the clue works.
(Other definitions for pave that I've seen before include "Cover with flat stones" , "Cover with slabs" , "Dress with stone etc" , "Cover with flagstones" , "Cover with flags" .)