all tire pressure gauges measure RELATIVE air pressure... that is, the pressure difference between the air inside and outside the tire. so a 75PSI tire at sea level will "feel" as hard as a 75 PSI tire at the top of mt everest

That said, I took the liberty of calculating how much the pressure would increase if you were to start your ride at 300m and climb to a 2700m elevation:

a measly 3.6 PSI!!!

so I doubt you have any reason to worry about your tires popping as you climb the mountain .