Why do cement pavements have to be made piece by piece, with gaps? Tell me the reason for doing this.

This crack is a contraction joint, and the cement pavement has the function of thermal expansion and cold contraction. This kind of contraction joint is used to protect the pavement when the temperature is high in summer. Without this crack, as soon as the pavement expands and there is no place to squeeze, it will arch up somewhere in the middle and the pavement will be broken. Moreover, the amount of construction at a time cannot be unlimited, and it can only be done piece by piece.

In addition, the phenomena of thermal expansion and cold contraction include:

1. The water pipe will freeze in winter, and the water will become bigger after freezing, but the water pipe will shrink when it is cold, so the water pipe will burst.

In summer, sometimes the road surface will arch upwards, which is caused by the expansion of the road surface, so there are gaps on the road surface at regular intervals.

Because the factory is very hot during production, the gas will expand. After cooling, the volume of gas inside decreases, and the atmospheric pressure outside is greater than that inside, so it is difficult to open it. With a little heating, you can open the can easily.

Soak the boiled eggs in cold water, and the eggs will be easily peeled off. This is because eggshells and protein contract differently.

High-voltage lines sag a lot in summer and are tight in winter.