Liquefaction is an appearance during the compaction of dry concrete when making concrete pipes with vibration. Liquefaction is a process that airs are expelled out of the concrete, and the aggregate of concrete is compacted together firmly.
Why is liquefaction so important for making dry-precast concrete products by vibration machine? During the liquefaction, the extra air is expelled out of the concrete, and each element of the concrete are compacted and bonded with each other in high level. The mortar produced during the process could full-fill tiny gap and space, that enables to increase the strength and the density, as well as the low-permeability.
What is liquefaction looks like? Have you ever boil waters? The air bubbles keep coming out of the surface the of water. Liquefaction of concrete looks like that. But the difference is, liquefaction is a temporary scene when most of the air is expelled out of the concrete, the air bubbles are less and less visible.
You may wonder that liquefaction is very common in wet precast, but dry concrete? Not sure.
However, liquefaction happens in dry concrete too. The vibration is matters a lot for the appearance of liquefaction. Try to adjust the vibration to high frequency (5000-6000rpm) and low amplitude (close to the self-amplitude of concrete), you will get a perfect finish concrete product.
You may not tell the differences of machines whether they can make the concrete liquefy or not. But the finished concrete product won’t lie.
The concrete product that has been fully compacted and liquefied by high-frequency vibration has a smooth surface and visible density, while the one hasn’t been produced in this way came out with a surface full of pores.