With greater precompression forces you'll certainly increase the likelihood of blow-outs and increase congestion of rebar/tendons. You might want to choose a concrete mix design with higher strength and lower viscosity.
Roger -
there are a number of causes of concrete deterioration primarily:
alkali-silica reaction
freeze-thaw damage
corrosion of reinforcing bars
sulfate attack
physical forces (abrasion, impact, etc)
Because you are asking about sulfur pits, as concrete engineers the first thing that comes...