Understanding of vacuum degree of vacuum grouting in prestressed channel

Pressure is usually divided into gauge pressure and absolute pressure, and its unit symbol will be indicated as (g) at the end of the pressure unit-this is gauge pressure, and (a or abs) this refers to absolute pressure.

Usually, there is a minus sign in front of the vacuum degree, indicating that this value is gauge pressure, which is calculated according to absolute pressure-local atmospheric pressure. If the value is negative, it indicates a vacuum state; if it is positive, it indicates that the pressure exceeds atmospheric pressure.

It can be seen that -0.08~-0. 1mpa does not mean that this value is 0.8~ 1 atmospheric pressure at all.

For example, 0.8 atmospheric pressure =0.8* a standard atmospheric pressure (0.1kloc-0/325mpa), which is the value and significance of 0.8 atmospheric pressure.