PH is a measure of alkalinity (or acidity, technically). We are concerned with alkalinity in the flooring biz because cement is naturally alkaline, and the glues we use can be broken down by excessive alkalinity.
MVER stands for Moisture Vapor Emission Rate. Specifically, we concern ourselves with measuring the amount of water vapor that is being released by the concrete that we are gluing our floor to. Excessive vapor transmission will affect the glue.
Ernesto (I think) is considering that as moisture moves up through a concrete slab it brings the highly alkaline compounds in the slab up to the surface with it. Carbon dioxide in the air reacts with the calcium hydroxide in the concrete and forms calcium carbonate. This process lowers the alkalinity of the carbonated concrete to about PH9.
It would make sense then that fresh green concrete would be both highly alkaline and have high moisture emissions. And as the concrete vapor emissions drop over time, and the concrete surface carbonates, the PH falls as well as the MVER.
Where we can prove this correlation doesn't fall on a nice graph we can use to tie these phenomenon together is in the case of a old carbonated and highly porous slab that allows sub-surface moisture to move through it quite readily, however the PH is extremely low. Another case is a quite dry slab poured on a retarder that we grind or abrade the surface carbonation off, exposing the more alkaline core, yet the concrete is emitting very low levels of vapor.
To further muddy the waters, concentration of CO2 in the air, concrete density, amount of pore water, age of concrete, and I'm sure other factors I'm not considering will come into play changing how PH and MVER relate in any given slab.
Excellent question, and I sure hope I didn't mess up my chemicals in my answer. I need to re-read this kind of stuff every year or I forget it quick!