Water absorption

The water absorption is a physical parameter of a substance, substance mixture or material and not with the process of drinking to be confused.

The technical term plays an important role in standards and technical regulations on building materials . Their ability to absorb water depends on their surface properties and porosity and is crucial for their frost resistance .

Certain materials - or product variants - with high water absorption are only suitable for indoor use. Their water absorption capacity can even be desirable here in order to buffer the relative humidity of the room air . Water absorption is also desirable with desiccants (e.g. zeolites or silica gel ).

On the other hand, the lowest possible water absorption is an important parameter of insulating and insulating materials - it is not desired here .

Certain substances must be protected from water absorption so that their purity or structure is retained. Examples are concentrated sulfuric acid , salts , alcohols .

In the field of soil mechanics , the term is also used for the properties of soils .

Methods of determination

The water absorption WB is the output part by a sample after complete drying not more includes:

• in  mg : ${\displaystyle \mathrm {WB1} =m_{\mathrm {q} }-m_{\mathrm {e} }}$
• in percent: ${\displaystyle {\begin{aligned}\mathrm {WB2} &={\frac {m_{\mathrm {q} }-m_{\mathrm {e} }}{m_{\mathrm {e} }}}\cdot 100\%\\&=\left({\frac {m_{\mathrm {q} }}{m_{\mathrm {e} }}}-1\right)\cdot 100\%\end{aligned}}}$

With

• Mass  m _{q of} the swollen sample
• Mass  m _{e of} the dried sample.

See also

• Water content
• Dry matter