Analyzing the five states of water in building wood, we can use wood everywhere in our life. For wood, we also know that the states of water in building wood are different at different times. What are the specific states? The following manufacturers will explain the five states of water in building wood. What are the five kinds?
Raw wood state: The newly cut wood is in the raw wood state. The cell cavity and cell wall contain water. The amount of free water varies with the seasons, and the combined water is in the saturated state.
Fiber saturation point: If the raw material is placed in the environment of 100% relative humidity, the free water in the cell cavity evaporates slowly. When there is no free water in the cell cavity and the binding water in the cell wall is saturated, the state is called the fiber saturation point. The moisture content of the fiber saturation point is generally 30%.
Air-drying state: When raw wood is naturally dried in the atmosphere, the final water balance state is called air-drying state. Generally speaking, the air-drying water content in southern China is higher, about 15%-16%, while that in northern China is about 12%-13%.
Absolute drying state: When free water and bound water in wood are completely removed, the state of wood is called absolute drying state.
Fiber saturation point is a critical state. Generally, the amount of free water has little effect on the physical properties of wood, but the amount of combined water has a great influence on the physical and mechanical properties of wood.
Dry shrinkage and wet swelling of wood refers to the phenomenon that the wood cell wall will shrink or swell when the moisture content of wood is desorbed or absorbed in the moisture content area from the absolute drying state to the first saturation point. When the moisture content of wood is higher than the fiber saturation point, the change of moisture content will not cause the wood to shrink and swell. The macroscopic performance is wood. Reduction and expansion of size.