Surface condensation forces cracks

Water taken up by solid materials is generally classified as water bound by physical forces or water bound by chemical bonds. Physically bound water includes adsorbed water, trapped or liquid-inclusion water, and absorbed water. The physical adsorption of water occurs when water condenses or is held on the surface the surface includes the cracks, crevices, etc. of real materials. Liquid inclusion occurs during the crystallization process when bubbles of water are trapped. 

The capillary condensation is a well known phenomenon in nature and is in most cases associated with the condensation of water in pores and cracks with hydi ophilic surfaces. A curved meniscus is formed due to the surface tension of the water-vapour interface. As a result of the change of pressure across this meniscus, a strong attractive force acts between the two surfaces. The phenomenon is known for quite a long time and has been explained by Lord Kelvin back in 1871 [15] with his famous equation [16]. 

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